Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas         REHABILITATION & ECOLOGICAL    ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                  ACKNOW...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                   TABLE...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasCHAPTER 5GENERAL MEASURES IN REHABILITAT...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                     Gabions or wire-bou...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                      LI...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                      LI...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                      LI...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                      LI...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                   LIST ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areaswelfare are equally significant. As such...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas         These areas have open pits and ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Table 1. Total heavy metal content (in ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasSubstrate is generally very loose and pl...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas      F. Ecological        • Flora (Vege...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas    B. Geological Features          1. D...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasMineral Sampling Field Lay-out        An...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasProblem Diagnosis, Analysis and Interpre...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasAnalyzing Poor Plant Growth Performance ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas            SCHEMES TO CONTROL          ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasProject Planning and Design        The s...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                                        ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas         More often, not just a single s...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasIdentifying Candidate Species         Sp...
22                                        Table 3. Leopold Matrix of Species for Rehabilitation of Mining and Volcanic Deb...
SPECIES                                         ELEVATION RANGE (M)           DROUGHT TOLERANCE         pH         REMARKS...
24                Scientific Name                                 ELEVATION RANGE (M)            DROUGHT TOLERANCE        ...
SPECIES                                              ELEVATION RANGE (M)             DROUGHT TOLERANCE                    ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasIt is worthy elaborating some of the mor...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas           After being affected by droug...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas          The chief drawbacks however ar...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas        Phytoremediation is the ability ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasStackhousia tyronii (Sunflower)         ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas      Narra (Pterocarpus indicus)       ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas                      •   water stress  ...
Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasFig. 29. Comparative growth    performan...
A Research Compendium For Mining And Volcanic Debris-Laden Areas
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A Research Compendium For Mining And Volcanic Debris-Laden Areas
A Research Compendium For Mining And Volcanic Debris-Laden Areas
A Research Compendium For Mining And Volcanic Debris-Laden Areas
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A Research Compendium For Mining And Volcanic Debris-Laden Areas

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REHABILITATION & ECOLOGICAL
RESTORATION R & D FOR MARGINAL &
DEGRADED LANDSCAPES AND SEASCAPES

A Research Compendium
FOR MINING AND VOLCANIC
DEBRIS-LADEN AREAS

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  • Ang yaman ng Palawan ay yaman ng Pilipinas It is known as the Philippines’ Last Ecological Frontier. It has 40% of our country’s remaining mangrove areas, 30% of our coral reefs, at least 17 Key Biodiversity Areas (KBAs), 2 UNESCO World Heritage Sites, and 8 declared Protected Areas (PAs). It is unmatched anywhere in the country
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  • Write a comment...NO TO MINING IN PALAWAN and other Key Biodiversity Areas, Natural Forests, Island Ecosystems, Critical Watersheds and Agricultural Areas!
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  1. 1. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas REHABILITATION & ECOLOGICAL RESTORATION R & D FOR MARGINAL & DEGRADED LANDSCAPES AND SEASCAPES A Research Compendium FOR MINING AND VOLCANIC DEBRIS-LADEN AREAS DEBRIS- Department of Environment and Natural Resources Ecosystems Research and Development Bureau
  2. 2. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas FOREWORD Research information and technologies on the restoration of minewastelands have proliferated in the past years, however, access to them by thegeneral public is quite limited. This Research Compendium on Mining Areasand Volcanic Debris -laden Areas has been developed to serve as a sound andthorough basis for selection of appropriate, effective and efficient strategies forthe restoration of damaged mining and volcanic ash-laden areas of the country. This undertaking included an initial compilation of past and recentscientific and successful rehabilitation works on mine-waste lands and volcanicash- laden areas locally and internationally which were organized, integratedand synthesized into a manual to reflect relevant research strategies andtechnologies for possible verification and application under local site specificconditions. MARCIAL C. AMARO, JR., CESO III Director i
  3. 3. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas PREFACE This Research Compendia on Rehabilitation and Ecological RestorationR & D Technologies for various Ecosystems was published through the efforts ofthe Ecosystems Research Development Bureau and its regional research fieldcounterparts, i.e. Ecosystems Research and Development Sectors. Researchinformation was gathered from all Regions including those from recent booksand the internet. Ecosystems studied include: critical watersheds, degradedmine waste areas, volcanic debris laden areas, marginal grasslands and uplands,damaged urban and coastal sites. While research and technology information generated in the past yearshave proliferated, the changing needs of time require that recent technologiesbe collated, integrated, analyzed and synthesized as a basis of decision-makingin verifying the effectiveness and efficiency of said technologies. Managers anddevelopers particularly in degraded areas need vital source of broad set ofinformation from which to choose from. This manual hopes to be a meaningfulguide to hasten rehabilitation efforts in these areas. EVANGELINE T. CASTILLO, Ph. D. National Program Leader/Coordinator Rehabilitation Banner Programii
  4. 4. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas ACKNOWLEDGEMENT This publication is indebted to the following agencies and people who,in their own way, contributed for the completion of this material: ERDS Regional Technical Directors and regional focal persons for thisproject who contributed in gathering information and articles on the differentrehabilitaion strategies, particularly on species common in the region; Local mining companies for their collaborative efforts in sharinginformation on the different rehabilitation initiatives they have beenundertaking; Technical Staff of ERDB in gathering the different technologies fromvarious agencies implementing projects on mining; DENR-ERDB Management for funding the implementation of thisbanner program and the publication of this compendium; The different library staff of the following offices: DENR Central Library;College of Engineering Library, UPLB; ERDB Library; College of Forestry, UPLB;Environment and Management Bureau; and UP Geological Institute Library, UPDiliman for giving project researchers access to their facilities and resources; To Ms. Celeste Gonzaga for the editing job; The GDAERD family, particularly, the support staff for their effort inencoding, compiling and for their assistance in the final reproduction of theseCompendium. EVANGELINE T. CASTILLO, Ph. D. Program/Project Leader AIDA C. BAJA— LAPIS / MARIA dP. DAYAN Project Leaders iii
  5. 5. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas TABLE OF CONTENTSFOREWORD iPREFACE iiACKNOWLEDGMENT iiiTABLE OF CONTENTS ivLIST OF FIGURES viiLIST OF TABLES xLIST OF APPENDICES xiCHAPTER 1INTRODUCTION 1 Philippine Mining Industry and Its Environmental Impact 1 Volcanic Eruptions and Impacts of Volcanic Ash Deposits 4CHAPTER 2PURPOSE OF THE COMPENDIUM 5CHAPTER 3DESCRIPTION OF MARGINAL AREAS 6UNDERSTANDING THE SITE CONDITIONS 6 Mining Areas 6 Mine spoils/waste dump site 7 Mine tailing areas 8VOLCANIC DEBRIS-LADEN AREAS 9CHAPTER 4PRELIMINARY SITE CHARACTERIZATION, ASSESSMENTS 11AND PROBLEM DIAGNOSIS Micro-site Assessment Procedures 11 Problem Diagnosis, Analysis and Interpretations 15 Mining Areas 15 Volcanic Ash-Laden Areas 15 Analyzing Poor Plant Growth Performance in Mining Sites 16 Analyzing Erosion Problems for Determination of 16 Appropriate Measures Project Planning and Design 18iv
  6. 6. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasCHAPTER 5GENERAL MEASURES IN REHABILITATION 19VEGETATIVE MEASURES 19 Proper choice of plant species for mining land rehabilitation 19 Identifying Candidate Species 21 Potential Grass species 26 Potential Hedgerow/Livepole Species 28BIOREMEDIATION MEASURES 28 Finding Plants with Bioremediation Potential 28 Types of Metal Phytoremediation 29 Hyper-accumulators 29 Thlaspi caerulescens 29 Stackhousia tyronii 30 Pteris vittata 30 Hibiscus cannabinus 31 Brassica napus 31 Mycorrhiza, a Symbiotic Microorganism with 31 Phytoremediation Potential Vetiveria zinazoides 34 Imperata cylindrica 34 Microbial Remediation Potential by other microorganisms 34BIOENGINEERING MEASURES 35 Geomats 36 Extruded geogrids 36 Woven geogrids 37 Geocells 37 Hexagonal wire mesh products (HWM) 38 Jute netting 38ENGINEERING MEASURES 40 Structural Measures and their Application 41 Retaining Wall 41 Loose rock or stone check dam 41 Pole or log check dam 41 v
  7. 7. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Gabions or wire-bound loose stone/rock check dam 41 Rock Gabions 41 Riprap or stone terrace 43 Rock Riprap 43 Bench terraces 43 Increasing Survival and Growth of Plant Species for Mining 43 Land Rehabilitation and Volcanic Debris-Laden areas thru Effective cultural management practices Addition of Soil Media as Base Material 44 Liming Application 44 Inoculation with Fitted Mycorrhiza 46 Organic Fertilizer Application 47 Use of Coir Fiber Amelioration Blanket 47CHAPTER 6REHABILITATION STRATEGIES IMPLEMENTED BY 48MINING COMPANIES Philex Mining Corporation 48 Rapu-rapu Polymetallic Project 48 Atlas Consolidated Mining Development 48 Corporation Dolomite Mining Project 49 Rio Tuba Nickel Mining Corporation 49 Bagacay Mining Company 49 Benguet Corporation 50 Philex Mining (at Sto. Niño) 50REHABILITATION STRATEGIES IN PINATUBO VOLCANIC ASH-LADEN 51AREASSHOPLIST OF APPROPRIATE SPECIES AND TECHNOLOGIES FORREHABILITATION 53REFERENCES 54APPENDICES 60vi
  8. 8. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas LIST OF FIGURESFigure Page 1 The unsightly landscape left by Atlas Mining Company, Cebu. 2 Such inactive or abandoned open pit mines are testimonies to the environmental degradation of mining. 2 Mining waste materials from the dump site are transported 2 to the river below leading to the communities. Most of the ricelands close to the waterways were covered with silt, laden with toxic heavy metals (Suyoc, Placer, SDN). 3 Mined-waste dumps remain barren for years continuing to 3 erode through time. 4 Basic understanding of the problems which are the 6 foundation for determination of appropriate solutions: physico-chemical conditions of the media (not soil but mineral media), micro-climate (atmospheric conditions of the immediate environment), biological (flora, fauna, microflora/ microfauna) and economic considerations of proposed rehabilitation measures to be employed. 5 The inhibiting effect of cadmium on the growth of oats. 7 6 Mine waste dump or mine spoils comprise the overburden 7 and interburden materials composed mainly of hard rocks, silt, and sand that are strongly acidic. It is also devoid of major and minor nutrients to support plant growth. 7 Slope stabilized by bench terraced in the mine waste dump of 8 Antamok, Itogon, Benguet. 8 Mine waste dump area of Manila Mining Company at Placer, 8 Surigao del Norte. Periodic landsliding and slumps have resulted from its unstable steep slopes. 9 Even with rehabilitation efforts starting either from the base 8 and top ridge and flat areas along valleys, sloping areas remain unvegetated. Ecological succession failed to proceed in these areas. 10 Mine tailing areas in Maricalum Mining Company tested with 9 Imperata grass planted at 1 meter spacing. The scheme was reported to be a failure. vii
  9. 9. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas LIST OF FIGURES Figure Page 11 A close-up photo of the very fine sandy materials. Note that 9 Mimosa pudica, a nitrogen-fixing species was able to survive the harsh environment. However, the poor microclimate have limited its capacity to expand outward. 12 During rainy season, massive erosion of volcanic ash and 10 lahar area were experienced due its quite loose mineral particles. 13 Plant indicators present in the mined-out area shall be 12 photo-documented. 14 Cogon with purplish blades is an indicator of low 12 phosphorus content. 15 Media productivity contour map using pH values. 14 16 Mere establishment of plant species without consideration 16 of the environmental limitations in the planning process resulted in poor growth performance affecting survival in the long run. 17 Two basic strategies or lines of defenses in arresting soil 17 erosion. 18 Sloping mine waste of Mogpog, Marinduque with landsliding 17 and gullying starting from the middle slope to the bottom of the slope. 19 Its extensive and thick root system binds the soil and at the 26 same time makes it very difficult to be dislodged an extremely tolerant to drought. 20 When buried by trapped sediment, new roots are developed 26 from nodes and vetiver will continue to grow with the new ground level eventually forming terraces, if trapped sediment is not removed. 21 Vetiver grass turned brown in peak summer but regrew 27 when intermittent rainfall came during the next season (Pilot demonstration site at Placer, Surigao Del Norte). 22 Construction of a bamboo-reinforced embankment in 27 progressviii
  10. 10. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas LIST OF FIGURES Figure Page 23 Morphological characteristic features of Thlaspi plant. 29 24 Sunflower is easily available species for propogation. 30 25 Braken fern possess dark green large, long leaflets 31 compared to other ferns. 26 Various varieties of ferns consistently thriving in almost all 31 mined-out and mine spoils throughout the country. 27 Mechanisms of how mycorrhiza help respond to metal 32 toxicity. 28 Robust batino plant in the mine waste dump site. 32 29 Comparative growth performance of Agoho (Casuarina 33 equisetifolia) in mine waste areas of Itogon, Benguet. 30 Spores of vesicular –arbuscular (VA) mycorrhiza Glomus sp. 33 Mycorrhiza has been identified as a major player in removing of heavy metals in soils like the mine waste areas. 31 Geomats main function is to protect the land against 36 superficial erosion caused by the impact of rain drops and rills, or the flood action for river channels. 32 Extruded geogrid polymers are commercially available 37 materials. 33 Geogrid materials may also be woven or bonded. 37 34 Its function is to hold soil or other loose material in place 37 and to prevent the superficial soil from slipping down slopes. 35 Woven geotextile are double-twisted materials. 38 36 Biomats and biotextiles are similar to geomats in function 38 but differ in that they come from biological materials. 37 Close-up view showing jute netting in a roadbank in Cavite. 39 38 Biomat Installation Procedures 39 39 Gabion illustration of Installation Design (Front View) 41 ix
  11. 11. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas LIST OF FIGURES Figure Page 40 Gabion illustration of Installation Design (Top View) 42 41 One of the most practical measures preferred for mining 43 Rehabilitation 42 Soil can be enclosed by organic materials such as coir for 47 moreassurance of survival under harsh conditions. 43 Mine waste area of Benguet Corporation in Antamok, Itogon, 50 Benguet prior to rehabilitation (left). 44 The same mine waste area with 2-year old benguet pine 51 inoculated with mycorrhiza (right) 45 Mycorrhizal rain tree growth performance after three years. 51 LIST OF TABLES Table Page 1 Total heavy metal content (in mg/kg) on-site and 7 corresponding environmental and health threshold levels. 2 Blocking Scheme in a slope for determination of soils for pH 14 and other laboratory analysis 3 Leopold Matrix of Species for Rehabilitation of Mining and 22 Volcanic Debris Ash-Laden Areas 4 Relative Neutralizing Power (RNP) for common lime 45 materials.x
  12. 12. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas LIST OF APPENDICES Table Page 1 Biophysical Requirements of Species Suitable for 61 Rehabilitation of Mining & Volcanic Debris-Laden Areas 2 Seed Technologies for Various Species Suitable for 76 Rehabilitation of Mining & Volcanic Debris-Laden Areas 3 Nursery Techniques and other Cultural Management 92 Practices of Species Suitable for Rehabilitation of Mining & Volcanic Debris-Laden Areas 4 Pest and Disease Control Strategies in the Nursery and 107 Plantation for Species Suitable for Mining & Volcanic Debris -Laden Areas 5 Field Plantation Cultural Management Techniques of 112 Species Suitable for Mining & Volcanic Debris-Laden Areas 6 Inert Materials Functions 123 7 Cost Analysis of Coco coir Technology 124Plate No. Page 1 Cocomat Application and Installation Techniques. 125 xi
  13. 13. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Chapter 1 INTRODUCTIONPhilippine Mining Industry and Its Environmental Impacts The Philippines is among the world’s richly endowed countries in termsof mineral resources. It ranks second in the world’s source of chromite andconsidered as one of the largest in the world. The country is projected to be thenext mining wonder in the next few years as the country’s gross productionfrom local minerals is expected. Also, as further projected, the country is eyed asthe mining country of the Pacific region by 2010. Recent figure of miningcontribution to GDP in 2005 was 68.4 billion pesos which doubled the grossproduction in 2002 of 35.2 billion (Manila Bulletin and Philippine Star, 2007).The total exports of mineral and mineral products have doubled from US$ 820million in 2005 compared with the recent value of US$ 206 billion. The mining industry plays an important role in the country’s economicdevelopment as it has increased direct employment from 101,000 in 2002 to141,000 which is a significant portion of the population and has indirectly givenother income generating opportunities. Moreover, the industry paid taxes, feesand royalties of about PhP 3.1billion in 2005 which is more than double the2002’s PhP 1.4 billion. Mining activities are governed by rules and regulations and strictcompliance to measures abating environmental degradation due toindiscriminate mining processes are closely monitored by multi-sectorstakeholders to ensure that a responsible mining is well in place. It is the desireof the government that there should be balanced consideration betweensocio-economic gains and environmental accountability while engaging inmining. However, it is a sad reality that in the course of any mining activity,unavoidable physical damage to ecosystems and destruction to habitat arecommitted. Open-pit mining clears the vegetation covering the deposits,inevitably exposing the soil and permanently changing the landscape and landuse (Fig. 1.). 1
  14. 14. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Fig. 1. The unsightly landscape left by Atlas Mining company, Cebu. Such inactive or abandoned open pit mines are testimonies to the environmental degradation of mining. One critical activity in mining is the disposal of mining wastes. Wastematerials usually drains into the major water systems. The transport of quiteloose particles, medium to large rocks and boulders from waste dump areasbecomes inevitable (Fig. 2). Fig. 2. Mining waste materials from the dump site are transported to the river below leading to the communities. Most of the ricelands close to the waterways were covered with silt, laden with toxic heavy metals (Suyoc, Placer, SDN). The mining process exposes heavy metals and sulfur compounds thatwere previously locked away in the earth. Rainwater leaches these compoundsout of the exposed earth, resulting in "acid mine drainage" and heavy metalpollution that can persist after the mining operations have ceased. Similarly, rainwater on piles of mining waste (tailings) can adverselytransfer pollution to freshwater supplies. In the case of gold mining, cyanide isintentionally poured on piles of mined rock (a leach heap) to chemically extractthe gold from the ore. Some of the cyanide ultimately finds its way into nearbywater. Huge pools of mining waste "slurry" are often stored behindcontainment dams. If a dam leaks or bursts, water pollution is guaranteed. The increasingly higher quantities of these heavy metals being releasedinto the environment by anthropogenic activities, primarily associated withindustrial processes, manufacturing and disposal of industrial and domesticrefuse and waste materials pose a major environmental and human healthproblem which needs an effective and affordable technological solution. Heavymetals contaminate the soil and water. Particularly affected are irrigationfacilities posing threat to agricultural productivity and destruction of adjacentmarine ecosystems. Thus, in every mining activity, negative consequences tothe environment and various ecosystems are manifold and impacts to human2
  15. 15. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areaswelfare are equally significant. As such, prior to setting any mining industry,mitigating measures and rehabilitation plans are prescribed in all phases of theactivities. In 1995, the guiding principles emphasized by the government were thepursuance of responsible mining, rehabilitation of abandoned mines and tosafeguard the ecological integrity of areas affected by mining. Vast mining areas however lie unsightly to the public as they haveremained for decades as abandoned without any rehabilitation efforts made(Fig. 3). Fig. 3. Mined-waste dumps remain barren for years continuing to erode through time. In the course of mining operations in the past, major environmentalcatastrophes have placed mining industry in jeopardy. Case in point was in1996, whereby toxic mining wastes of Marcopper Mining Company inMarinduque spilled into the main waterways which was caused by itsdefective waste disposal facilities. This resulted in millions of fish kill whichsignificantly affected fish catch, and threatened the health and livelihood of thepopulation living in nearby coastal communities.The pit of Atlas Mining inToledo City, Cebu gave way to the clogged drainage that released acidic waterto the sea that caused the poisoning of marine life along the coastal areas. Thelatest incident was in Rapu-rapu Island where high level of cyanide was releasedin the coastal zones that killed fishes. Mining companies have been penalizedby suspension of operations and payment of a huge sum of money. This servedthem a lesson to abide by the regulations as provided by the Philippine MiningAct of 1995. To date, there are 65 non-performing mining tenements that werecancelled, representing 68,000 hectares of mineral land which is open to seriousinvestors for development (Reyes, 2007). Out of these, 24 were alreadyabandoned and need immediate rehabilitation (MGB, 2007). These areas wereleft out after several years of mining operations leaving behind toxic wastematerials, overburdened areas that are stony, rocky and acidic. 3
  16. 16. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas These areas have open pits and mine tailings. Aside from this, there arelarge portion of reforested mine waste areas with plants of poor health statuswhich were observed to die prematurely.Volcanic Eruptions and Impacts of Volcanic Ash Deposits Aside from mine waste areas, volcanic ash-laden areas pose anothergreat challenge in rehabilitation. The eruption of Mt. Pinatubo in the early1990’s has destroyed vast tracts of agricultural land in adjacent provinces. Witha stroke of nature, millions of tons of volcanic ash, mudflow carrying pyroclasticmaterials and other debris were deposited on the once productive areas turningthem into barren and idle areas. Aside from the tremendous losses of life andproperties, the vegetation which provides the basic needs of man for food andshelter, clean air and water has been totally devastated. There is an urgent needto find prompt research solutions to the vegetative rehabilitation of thedegraded areas which require primary succession. In deep-volcanic ash laden areas wherein agricultural crops would bedifficult to grow, long–term species such as trees would be the most suitable.Both the species and strategies for afforestation are wanting. Plant species musthave the ability to promptly colonize the thick ash-laden sites. To wait fornatural ecological succession to occur starting with lower forms of life may betoo long and impractical to meet the urgent needs of our people. Successfulafforestation strategies must therefore be characterized by their efficiency toshortcut the route of long-term ecological succession.4
  17. 17. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Chapter 2 PURPOSE OF THE COMPENDIUM This compendium is intended to provide the necessary information andtechnologies using plant species for vegetative restoration, as well as otherengineering strategies, their combinations or mixes that can be adopted to ensuresuccess in rehabilitation works. The data were gathered from various research outputs from publishedarticles and journals, as well as from documented experiences and success storiesthat have shown positive results. When research literature were still foundfragmentary, the research team (comprising ERDB and regional researchcounterparts) supplemented their research data from those coming from variousregulatory and research institutions and integrated R & D related subject mattersto form science-based protocols for rehabilitation. This compendium hopes toprovide several potential strategies to choose from to suit specific conditions ofdamaged areas. The contents of the compendium include the status of Philippine miningindustry, description of marginal sites, purpose of the development of thecompendium, site characterization assessment and problem diagnosis,rehabilitation measures and/or technologies in mining and volcanic debris-ladenareas. In the Appendices, each common plant species for mining were categorizedinto tables where selection can be done for appropriate application inrehabilitation using vegetative means. Each species was described morphologicallyand characterized according to its site requirements, needed amelioration, controlmeasures for pest and diseases, and planting strategies. The complete informationof the species have been presented in the appendices in a matrix form (template)for easy reference. Information on several bio-engineering strategies to choose fromwere also provided for areas where vegetative measures would not be sufficient. It is envisioned that this compendium will be of valuable application to themining industry, watershed development, vegetation of denuded areas, restorationof places affected by natural disasters such as volcanic ash-laden, landslide areasand the like. The target client and users of the mining compendium will be thosewho are involved and engaged in rehabilitation work as mandated byenvironmental law and in compliance with the provision of Philippine Mining Act of1995. Furthermore, it is hoped that end-users of the compendium will find it as auseful guide in various stages of rehabilitation, reclamation and ultimately therestoration of disturbed sites into, at least a more productive if not in its originalstate. Likewise, may this compendium, with its assemblage of knowledge andpractices, fit well into the need for rehabilitation measures that will minimize thecost of a rather expensive rehabilitation works. 5
  18. 18. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Chapter 3 DESCRIPTION OF MARGINAL AREASUnderstanding the Site Conditions Before rehabilitation efforts could be done, it is imperative to develop acomplete understanding of the on-site conditions of these areas before we canprovide proper ecological solutions to them (Fig. 4) ON-SITE CONDITIONS Physico- Microclimate chemical Biological Economic Complete understanding the ecological status of the site for rehabilitationFig. 4. The basic understanding of the problems which are the foundations for determination of appropriate solutions: physico-chemical conditions of the media (not soil but mineral media), micro-climate (atmospheric conditions of the immediate environment), biological (flora, fauna, microflora/microfauna) and economic considerations of proposed rehabilitation measures to be employed.A. Mining Areas Mined-out areas consist of the open pits which are left behind after themining operation. They are characterized by being acidic and saline due tooxidation of pyretic materials (Yao, 2001). It is the most difficult sites forrehabilitation, because the pH fall below 4.0 that it plant survival and growthbecome nil if not ameliorated. These areas are usually untouched forrehabilitation unless bulk of soils is brought back to the site. In a gold mine area, heavy metals on site are way above normal levels.Typically, these include copper, arsenic, chromium, lead, zinc and strontium,elements that are later carried away by running water to the low lying areas.Table 1 shows the results of study in Australia ((Truong, 1995),have shown thatindeed heavy metal content in a gold mine exceeded the set threshold levels.The negative effect of them in plants is further reflected below (Fig. 5).6
  19. 19. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Table 1. Total heavy metal content (in mg/kg) on-site and corresponding environmental and health threshold levels. Heavy Metals Thresholds mgKg-1 Environmental Health GOLD MINE Heavy Metals mgKg-1 Total Content Arsenic (As) 20 100 Arsenic 1,120 Chromium (Cr) 50 - Chromium 55 Copper (Cu) 60 Copper 156 Manganese (Mn) 500 Manganese 2000 Lead (Pb) (Pb) 300 300 Lead 353 Zinc (Zn) 200 Zinc 283 General Plant Responses to Heavy Metal Toxicity Fig. 5. The inhibiting effect of cadmium on the growth of oats . Mine spoils/waste dump site are places where the originally removedlayers from mined- out areas are dumped. Because of periodic dumpedmaterials, rock materials therein are variable in terms of size and chemicalcomposition (Fig. 6 and 7). Fig. 6. Mine waste dump or mine spoils of Manila Mining Company at Placer, Surigao del Norte com- prise the overburden and inter- burden materials composed mainly of hard rocks, silt, and sand that are strongly acidic. It is also devoid of major and minor nutrients to support 7
  20. 20. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Fig. 7. Slope stabilized by bench terraced in the mine waste dump of Antamok, Itogon, Benguet. Because of general lack of homogeneity in a given site, collection ofmineral and their chemical analysis are preliminary part of site characterizationactivities. Sloping mine waste lands are often last choice for rehabilitation bydevelopers due to safety reasons (too steep slopes, unstable materials highlyprone to landsliding, and erosion (Fig. 8 and 9).Fig.8. Mine waste dump area of Manila Mining Company at Placer, Surigao del Norte. Periodic landsliding and slumps have resulted from its unstable steep slopes. Fig. 9. Even with successful rehabilitation efforts in mine waste dumps starting either from the base or top ridge and flat areas along valleys, sloping areas remain unvegetated. Ecological succession failed to proceed in these areas. Mine tailing areas are extensive mine waste dump areas which consist oflighter particles refuse material resulting from processing ground ore (Fig. 10).These materials have passed over a sieve in milling, crushing, or purifyingoperations and treated as inferior in quality or value. Materials consist of small,uniform, mostly sand and silt-sized particles (Fig. 11). Because of very finetexture, the soil is loose but the bulk density is high. This in effect controlsparticle aggregation and soil texture thus rendering very low water holdingcapacity.8
  21. 21. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Fig. 10. Mine tailing areas in Maricalum Mining Company tested with Imper- ata grass planted at 1 meter spac- ing. The scheme was reported to be Fig. 11. A close-up photo of the very fine sandy materials. Note that Mimosa pudica, a nitrogen-fixing species was able to survive the harsh environ- ment. However, the poor microcli- mate have limited its capacity to These areas are not only deficient in clay minerals and microorganismsbut are basically nil in organic matter, nitrogen, phosphorus and potassiumwhile excessive in heavy metals. Sand blasting during windy days causes rapidtranspiration resulting in the death of intolerant species. Although located in flatareas, erosion in these areas are also prevalent coming from wind sources.B. Volcanic Debris - Laden Areas The Philippine islands consist of several active volcanoes which fromtime to time erupted in the past years. These events brought about voluminousejection of volcanic gases, molten rocks, volcanic ash and other pyroclasticmaterials several kilometers into the air. Areas within the immediate vicinity ofthe volcano were buried to as deep as 50 to 100 meters. Spewed up materialsgenerally constituted dacite, andesite, basalt and pumice. As a result of eruption of volcanoes, volcanic debris, molten rocks andpyroclastic materials were deposited as loose materials in vast areassurrounding the volcano. The eruptions of Mt. Pinatubo in Central Luzon 1991and Mt. Mayon in Albay (still actively erupting) have left vast areas with twogeneral types of materials: 1) lahar-pyroclastic mudflow deposits which coveredtheir major drainage and 2) volcanic ash- deposited loose sand and silt materialswhich buried extensive low-lying grounds. Inasmuch as the majority of areaswhich now needed rehabilitation efforts are of the volcanic ash-laden materials,this compendia shall deal more on said topic. Generally the vast desert-like areas are often exposed to weatheringand pressures of extreme conditions that barely supports life. The volcanic ash 9
  22. 22. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasSubstrate is generally very loose and pliable thus prone to erosion, devoid ofnutrients for plants to grow and water is very limiting in the area. The sandy mineral particles that cover the thick land areas arecharacterized by low water holding capacity and require irrigation for the plantto survive. At the same time, even it is of poor water holding capacity, areasunder deep volcanic ash can easily be washed out by high intensity and heavyrainfall (Fig. 12). Fig. 12. During rainy season, massive erosion of volcanic ash and lahar area were experienced due its quite loose mineral particles. Assessment of chemical status of the volcanic ash with time revealedthat during the first month, the volcanic ash media was initially acidic due to theeffects of sulfur dioxide. But after this was leached and/or volatilized in theatmosphere, volcanic ash pH became neutral (values ranged from 6.0-7.2). ThepH status however decreased three years later. With mineralization process inthe later years, ash mean value ranged from 5.0-5.9. Although the mineral media attained high pH level, chemical analysisrevealed low concentration of macro and micro nutrients. In the sterile media,nitrogen, potassium and micronutrients content were all nil. Only phosphoruswas medium in content. There was also no starter microsymbiont found. Suchimbalance in the nutritional status, poor physical conditions (i.e. low waterretention capacity) and droughty atmospheric condition all redound to the needfor special strateg(ies) that would address all the limitations in order tosucceed in such areas. Natural succession takes a long process. But a system to accelerate thepace can be done in a much faster time thru current technologies. Startervolcanic ash-laden sites can be pilot tested to showcase the viability ofconverting desert-like conditions to a mini-forest cover in a much shorter timeimagined. Later, these nucleus areas are designed to be growing points toexpand ecological restoration of more areas in the long run.10
  23. 23. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Chapter 4 PRELIMINARY SITE CHARACTERIZATION, ASSESSMENTS AND PROBLEM DIAGNOSIS Proper diagnosis of problems besetting a site requires a ful characterization of the on-site biophysical conditions as well as the off-site socio-economic situation of nearby affected communities.Micro-site Assessment Procedures Because of the observed site heterogeneity, it is a basic step to conductmicro-site assessment of a proposed area to be rehabilitated. The following arethe procedures to be undertaken: 1. Collect baseline secondary information of the proposed mining area for rehabilitation prior to the on- site reconnaissance and field verification. 2. Site Characterization of Selected Site (s) The following specific site conditions of the chosen site(s) shall be characterized: Mine spoils/mine waste dumps – soil and fragmented rocks hauled and dumped on the surface of the mountain I. General site description A. Specific classification of mine waste area (mine waste/mine tailings) B. Location (Sitio, Brgy., Municipality, Province) C. Accessibility – distance from the nearest road networks from the nearest barangay. D. Boundaries – direction (N, E, W, S) E. Microclimate • Rainfall (secondary data) - Rainfall or precipitation is the amount of water that fall upon the earth. • Temperature (air and soil) - Temperature is the degree of hotness or coldness of the air. • Sampling of diurnal temperature range for the whole day (8, 10, 12, 2, 4 o’clock at least 3 sampling days using air/ soil thermometer) • Relative humidity (wet and dry bulb thermometer) 11
  24. 24. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas F. Ecological • Flora (Vegetation) -Observation on the presence of naturally growing plant species and occurring in the mined-out/mine waste dump areas must be properly photo-documented (Fig. 13 and 14). Fig. 13.Plant indicators present in the mined-out area must be photo- documented. Fig. 14. Cogon with purplish blades is an indicator of low phosphorus • Fauna- Observation of the presence of specific fauna (birds, insects etc.) in the area (faunal indicators). II. Detailed characterization of the micro-site A model area must have a minimum area of one (1) hectare. The whole area must be subdivided into compartment units depending on the natural limitations of land features (bodies of water, ridge, heterogeneity of the sites, etc.). A minimum of two major compartments may be selected to verify the technologies. Each compartment units must have its own individual micro-site characterization as a basis for the field treatment lay-out and application of future demonstration of different rehabilitation technologies. A. Topographical Features Terrain/slope (using abney hand level) Elevation (altimeter)12
  25. 25. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas B. Geological Features 1. Description (secondary information and field observations) • Type and nature of rock deposits (gold, copper, zinc, iron, chromite, silver, nickel, etc.) • Physical characteristics (description of rock fragments- relative size, variability of size, relative imperviousness, drainage (waterlogging) and aeration) • Erosion description (relative formation of rills, gullies and landslides) depths, extent/percentage of area affected and erodibility of loose rocks and mineral particles 2. Collection of mine waste media samples for physical and chemical analyses Basis of Media Sampling in the Field a. Narrow and long slope The occurrence of fertility gradient is usually more pronounced in sloping areas, i.e. with the lower portion more fertile than higher areas. Take mine waste media samples for physical and chemical property determination. Utilizing representative points along the contour of various contour/ slope locations (i.e. top, middle, and bottom), collect composite samples from at least 5 points. The distance in between 1 contour sampling line will depend upon the slope length, degree and heterogeneity. Get mine waste media samples from a depth of at least 30 cm. b. Media Heterogeneity If the area is very heterogeneous, a soil productivity contour map must be made. It is a simple but informative presentation of soil/media heterogeneity. It is advisable to conduct uniformity trial to assess the pattern of soil heterogeneity so that a suitable remedy can be achieved by proper blocking. Fig 15 is a slope subdivided into blocks ex. Column A, Row 1 as one unit (Table 2). The whole slope has 16 unit blocks. The map describes graphically the productivity level of the experimental site base on moving averages of contiguous unit. Values represent numerical pH. 13
  26. 26. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasMineral Sampling Field Lay-out Analysis of pH indicates blocks column a-row 1, column b-row 2 and column d-row 4 had the same pH value of 3 of the sampling area point representing that block. Column Column Column Column A B C D Row 1 3 3 3 5 Row 2 4 3 4 5 Row 3 4 5 4 3 Row 4 5 5 4 3 Table 2. Blocking Scheme in a slope for determination of pH and other laboratory analysis. pH 3 pH3 pH 3 pH 5 pH 4 pH 3 pH 4 PH 5 pH 4 pH 3 pH 4 pH 5 pH 5 pH5 pH 4 pH 3 Fig 15. Media productivity contour map using pH values In volcanic ash laden areas which are located in relatively flat areas, themedia are more or less homogenous in composition. Hence sampling scheme issimpler and fewer soil samples should be taken. A minimum of 5 samples forevery hectare would suffice. Quick field chemical, qualitative tests for pH, nitrogen, phosphorus andpotassium using Soil Testing Kit must be done.Laboratory Quantitative Analysis Quantitative chemical analysis of the following are also required: Macronutrients (Nitrogen, phosphorus, potassium, calcium, magnesium); Micronutrient (Zinc, copper, manganese, molybdenum, boron); Heavy metals (Gold, nickel, lead, etc).14
  27. 27. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasProblem Diagnosis, Analysis and Interpretations Characterization of site conditions has bearing on the analysis of thenature of various problems, and ecological factors for proper decision making.Usually, a summary of the major identified ecological problems besetting ourmining and volcanic ash laden areas are as follows:Mining AreasBarren site – droughty atmospheric conditions, high heat load, lack of waterRock, mineral media - variable or heterogenous materials; no soil; Generally dumped rocks are loose but compacted by tractors in mine waste areas; Nil symbiotic microbes; extremely acidic condition and increasing acidity thru time; fixed macro and microelements; possess high levels of unwanted heavy metals; hazardous to health when transported to waterways;Slope condition-steep slopes >30% Mine waste areas: steep to very steep; rills and gulley formation prevalent; Landsliding and slumps occurring; hazardous to human; Mine tailings: Flat areas; Occurrence of wind erosion;Flora - None or nil existing flora only ferns and mosses;Presence of company support for rehabilitation: Low in long abandoned mined-out areas LGU support: minimal Illegal panning and extraction activitiesVolcanic Ash laden Areas Media: Loose, fine mineral particles, high percolation rate, pH more or else neutral to basic, low in available nutrients. Type of Erosion experienced in the site: Wind erosion Flora: N-fixing trees like ipil-ipil, kakawate, agoho; pasture legumes; grass species associated with mycorrhizal i.e. Imperata, napier and talahib; Problems: Barren, desert-like areas hardly vegetated except if seeds are carried to the area by wind and germinates during wet season; heavy sedimentation and siltation of bodies of water; 15
  28. 28. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasAnalyzing Poor Plant Growth Performance in Mining Sites The choice of plant species is one of crucial steps in decision-making.Most often multiple problems arise in the course of plant development.Because of the very harsh environment in mining sites, that no plant is able tosurvive at the initial stage or there is low plant survival; remaining seedlingssuffer from stunted growth, nutrient deficiency and/or heavy metal toxicitysymptoms; and most often, trees have very poor health resulting to death earlyin life (Fig. 16.). Aside from these, sloping areas remain unvegetated, ecologicalsuccession failing to proceed in these areas. Choice of site to be rehabilitatedshould thus give priority to this erodible site or else active erosion advancingto rill and gully formations and occurrence of slumps/landslides are bound topredominate. Fig. 16. Mere establishment of plant species without consideration of the environmental limitations in the planning process resulted in poor growth performance affecting survival in the long run.Analyzing Erosion Problems for Determination of Appropriate Measures Erosion is the natural process whereby external agents such as wind orwater resource transport soil particles to far distances. In the wet tropics likethe Philippines, rainfall is mainly responsible for the removal of superficial layersresulting in rills or gullies of about 10-60 cm depth. Over time, rills and gulliesdeepen and these cause slopes to become over-steep, thus precipitatinginstability. In an open, sloping area (Fig. 17), the largest exposed surface groundarea can be economically controlled by covering the land by vegetation. Inparticular, cover crops, creepers and stolons can do this as first line of defense.16
  29. 29. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas SCHEMES TO CONTROL LINE OF DEFENSES COVERING FIRST LINE OF DEFENSES 2nd LINE OF DEFENSES STABILIZING Fig. 17. Two basic strategies or lines of defenses in arresting soil erosion Instability or deep-seated problems can arise on their own dependingon slope geometry’s inherent soil strength, ground or pore-water characteristics(Fig. 18). These are basically geotechnical/geological problems that have to beaddressed by proper studies and analyses. Through available computer programs, the evaluation of the stability ofslopes to determine their factors of safety against sliding or failure has nowbecome less tedious or laborious. Fig. 18. Sloping mine waste of Mogpog, Marinduque with landsliding and gullying starting from the middle slope to the bottom of the slope. On the other hand, shallow-seated problems, which lie in the 60-250cm depth, do not lend themselves for accurate computer program computation.They present a chronic problem in the wet tropics with the attendant heavyrainfall and inherent highly erodible slope materials. However, it is believed thisproblem can be dealt with very effectively by bioengineering measures. 17
  30. 30. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasProject Planning and Design The success of reclamation schemes will depend upon the systemsapproach employed in a unit area. (1) The type (s) of general measures applied (i.e. vegetative, or the combination of vegetative and engineering or bio-engineering, bioremediation (plants plus the use of their association with symbiotic microorganism), and engineering measure; (2) The choice of plant species (if it were vegetative or bio-engineering or bio-remediation); (3) The proper methods of establishment, amelioration measures and periodic care; (4) The concomitant best research technologies of growing said species (from the nursery to the field); the same holds true with engineering measures. The appropriate engineering measure, design and attendant methodologies for each specific site condition(s) must be employed. In planning for the selection of rehabilitation schemes, there is now along list of available developed technologies by industries, scientists andpractitioners from which to choose from. These include research informationand technologies on the following areas: Vegetative Measures: a. Species-site suitability (the selection of the right species for different locations), - Nursery production technologies (schemes of nursery and cultural management of a species) - Field establishment, soil amelioration measures and methods of application b. Bioremediation (biotechnology) application technologies in ecological rehabilitation, etc. c. Bio-engineering (combined plant and engineering) measures - Selected plant species (used for slope stabilization) - Innovations with combinations of plant and engineering measures - Inert materials manufactured by industries (intended to mimic natural plant cover) in combination with other schemes d. Engineering measures18
  31. 31. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Chapter 5 GENERAL MEASURES IN REHABILITATION The a foregoing discussions will deal on the broad spectrum of availabletechnologies, strategies, schemes and procedures to choose from dependingupon site situations and appropriateness. One may select several combinationsof schemes and measures for a given slope at varying locations. The systemsapproach is the best strategy, i.e. utilizing all possible schemes that wouldhasten restoration but also considering the available economic resources inapplying it.VEGETATIVE MEASURESProper choice of plant species for mining land rehabilitation Biological intervention refers to the use of versatile plant species(Single/combination of species) such that it can overcome many if not most ofthe problems confronting the restoration of degraded areas. The species musthave the following characteristics: (a) Ability to survive, adapt and grow normally under harsh condition; (b) Ability to grow at extremely low/high pH levels; (c) Potential to grow fast/ increase its biomass; (d) Tolerate drought and fire; (e) nitrogen-fixing and/or mycorrhizal associations (bioremediation potential); (f) Resistance to pests and diseases; (g) Potential to reproduce even under adverse environment; (h) Ability to phytoremediate (remove toxic heavy metals from the mine waste areas). The species should also possess other environmental functions. Theso-called bio-engineering strategy combines vegetative and engineeringschemes i.e. planting of certain species or mix of different plant forms in amethodical manner to provide structural cover for erosion control, slopestabilization and enhanced drainage system. The root system of plants used inthis strategy provides the protective function to the soil. For erosion control, the choice of vegetation is relatively wide.Generally, all plants are capable of providing some degree of protection,whether they are trees, shrubs or herbs: Shrubs and herbs, grasses and creepersare plant forms for immediate cover while trees provide the best long-termprotection against soil erosion and landslide. A variety of perennial species arebeing utilized as hedgerows to stabilize slopes and prevent soil for furthertransport downhill. 19
  32. 32. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas More often, not just a single species but a combination of trees, shrubs,grasses and creepers would be needed to provide a significant reduction insurface runoff and soil erosion. Vegetative measures are first choice becausethey are rather cheap materials, i.e more or less four times cheaper engineeringstructures. The basic considerations in the selection of tree species asbio-engineering measure against soil erosion and landslides are as follows: a. Plants must grow quickly to establish ground cover, have dense rooting systems and canopies. b. Roots and aboveground parts should grow rapidly in order to provide the required protection as soon as possible (rapid lateral growth of stems, leaves and roots for erosion control) c. Plant should possess deep and wide root system for good anchorage in the subsoil. A dense shallow root system can also be used because of the matting effect d. Rapid and dense growth of roots vertically for shallow-seated slope stabilization e. High root tensile strength and surface roughness for soil reinforcement f. Plant should produce a large volume of litter to improve the site. Leg- umes, in particular, can add considerable amount of nitrogen to the soil through symbiosis with nitrogen-fixing bacteria g. Prevent or minimize further transport of eroding materials h. Plant should form dense and wide spreading crowns or interlocking canopy as early as possible. i. Ability to be propagated vegetatively/asexually as large section cuttings as used in brush layering and as large diameter live poles. When using a species as live poles for slope stabilization, they must also have the following features: • Ability to resist impacts imparted by driving • Ability to grow long straight branches needed for ease in installation • Ability to withstand burial and impact by moving slope debris • Ability to propagate from large section hardwood cutting • Ability to grow rapidly and well when thickly or closely planted • Ability to root at depth; • Ability to grow in water logged condition • Has relative tolerance to insects & diseases • Grows into a tree it left unattended20
  33. 33. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasIdentifying Candidate Species Species selection is important to establishment success in the degradedmining area. If grown under unsuitable site conditions, generally, a specieswould not be able to cope up with the conditions hence affecting its status. Thespecies is prone to attacks of diseases, insects and pests. There are many candidate species having multi-functions: fast-growing,drought tolerant, with coppicing ability, and grows under nutrient deficientareas. After a thorough study on all environmental parameters matching withthe long list of species, those that are closely adaptable to the desert-likeconditions of mining and volcanic ash-laden areas were pre-selected andtabulated in a decision matrix table. Leopold Matrix in Appendix Table 8 summarizes the pre-selectedappropriate trees, shrubs, and grass species. Each species was describedmorphologically and characterized according to its site requirements. Thepackage of technologies of each species starting from seed technology, neededamelioration, control measures for pest and diseases, and planting strategiesare presented in the Appendix Tables 1 to 5 in a matrix form (template) for easyreference. 21
  34. 34. 22 Table 3. Leopold Matrix of Species for Rehabilitation of Mining and Volcanic Debris Ash-Laden Areas SPECIES ELEVATION RANGE (M) DROUGHT TOLERANCE pH REMARKS Scientific Name Common Name(s) 0 - 1000 0 - 1500 0 - 2000 G M E P Act Wt Nac TREES Acacia auriculiformis Japanese acacia, X X X X X X X pH range: 3 - 9.5 Best Auri, Wattle, Ear- growth: 5 - 6 pod wattle Acacia mangium Willd. Mangium X X X X Albizia procera (Roxb.) Benth. Akleng parang X X X X X X Aziodirachta indica A. Juss. Neem X X X X X X Calliandra calothyrsus Meissn. Calliandra X X X X X Casuarina equisitifolia L. Agoho X X X X Gliricidia sepium (Jacq.) Steud. Kakawate X X X X X X Leucaena leucocephala (Lam.) de Ipil-ipil X X X X X Wit. Piliostigma malabaricum (Roxb.) Alibangbang X X X X Benth. Var acidum (Korth) de Wit. Pithecellobium dulce (Roxb.) Kamachile X X X X X X Benth. Pterocarpus indicus Willd. Narra X X X X X X Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Samanea saman (Jacq.) Merr. Rain tree, Acacia X X X X X Trema orientalis (Linn.) Blume. Anabiong X X
  35. 35. SPECIES ELEVATION RANGE (M) DROUGHT TOLERANCE pH REMARKS Scientific Name Common Name(s) 0 - 1000 0 - 1500 0 - 2000 G M E P Act Wt Nac GRASSES Pennisetum clandestinum Hoehst. Ex Kikuyu grass up to 3000asl X X Chiov. Vetivera zizanioides Vetiver X X X X X SHRUB Tithonia diversifolia Wild sunflower 1000 - X X 2000 asl Albizia lebbekoides (DC.) Benth. Kariskis X X X X X X Alnus japonica / maritima (Thumb.) Alnus X X X X X Steud. Muntingia calabura Linn. Datiles X X X X X X X Piper aduncum L. Spiked pepper, X X X Hequillo de hoja Sesbania grandiflora (L.) Pers. Katurai, Agati, Bacule X X X X Zizyphus jujuba (L.) Lam. and Mill. Mansanitas X X X X X GRASSES Imperata cylindrica (L.) Beauv. Spear grass, alang-alang, cogon, bae mao 2300asl X X gen Kikuyo Kikuyo grass X X X Phyllostachys aurea Carr. Ex A & C. Chinese bamboo X Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Rivere Bambusa blumeana Kauayan tinik X23
  36. 36. 24 Scientific Name ELEVATION RANGE (M) DROUGHT TOLERANCE pH REMARKS SPECIES Common Name(s) 0 - 1000 0 - 1500 0 - 2000 G M E P Act Wt Nac SHRUBS Cajanus cajan (Linn.) Merr. Pigeon pea X X X X X CREEPERS Arachia pintic Krap & Greg. num. Amarillo froage X X X nud. (Cook) peanut, Pinto peanut Wedelia trilobata (L.) Hitche Wedelia up to 1300asl X X X Albizia falcataria (L.) Fosberg Molucccan sau x x x Alnus maritima (Thumb.) Steud. Alnus x x x x Alstonia scholaris (L) R. Br. Var. Dita x x scholaris Cassia spectabilis (L) Anchoan dilaw Eucalyptus camaldulensis River red gum x x Melia dubia Cav. Bagalunga x x Pinus kesiya Royle ex Gordon Benguet pine x x Spathodea campanulata Beauv. African tulip x Serialbizia acle (Blanco) Merr Akle x Trema orientalis (Linn.) Blume. Anabiong x x Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas
  37. 37. SPECIES ELEVATION RANGE (M) DROUGHT TOLERANCE pH REMARKS Scientific Name Common Name(s) 0 - 1000 0 - 1500 0 - 2000 G M E P Act Wt Nac Flemingia macrophylla (Willd.) Malabalatong x x Merr. Piper arborescens Palo verde x x x Grasses Thysanolaena maxima Tambo x Drought Tolerance: E - Excellent Soil Conditions: (withstands long drought period, AcT - Tolerance to 6-9 months dry season) acidic soils M - Moderate WT (well tolerant to extended - Wide tolerance to drought) soil conditions G - Good (moderately tolerant to extended dry periods) Nac - Not tolerant to acidic soils P - Poor (requires high, evenly distributed rainfall) Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas25
  38. 38. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasIt is worthy elaborating some of the morphological and functional mechanismsby some of these species:Potential Grass species Vetiver has been the identified most promising species because of its specialfeatures and functional versatility. Morphologically, it possesses extremely deepand massive finely structured root system, capable of reaching down to two tothree meters in the first year (Fig. 19). Fig. 19. Its extensive and thick root system binds the soil and at the same time makes it very difficult to be dislodged an extremely tolerant to drought. It has stiff and erect stems which can stand up to relatively deep waterflow (0.6-0.8m). It has dense hedges when planted close together, reducing flowvelocity, diverting run-off water and forming a very effective filter. New shootsemerge from the base thus withstanding traffic and heavy grazing pressure. Italso has the ability to regrow very quickly after being affected by drought, saltand other adverse soil conditions when the adverse affects are removed (Fig.20). Fig. 20. When buried by trapped sediment, new roots are developed from nodes and vetiver will continue to grow with the new ground level eventually form- ing terraces, if trapped sediment is not removed. Physiologically, vetiver has tolerance to extreme climatic variation suchas prolonged drought, flood submerged and extreme temperature from 140C to550C. It grows in a wide range of soil pH (3.0 to 10.5). It has a high level oftolerance to soil salinity, sodiity and acid sulfate. It can also tolerate toxic levelsaluminum, manganese, arsenic, cadmium chromium, nickel, copper, mercury,lead, selenium and zinc, on grass species.26
  39. 39. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas After being affected by drought, salt and other poor soil conditions, ithas the ability to regrow very quickly when the adverse affects are removed(Fig. 21). Bambusa blumeana (tinik) is considered a rehabilitation speciesbecause of its versatility, since it can grow either in the upland or lowland aslong as proper establishment and management techniques are followed. A studyon other bamboo species like bayog showed they are also effective in minetailing areas with survival rates of 99% and 97%, respectively. They are alsodrought resistant and they could tolerate water logging up to 63 days. Fig. 21. Vetiver grass turned brown in peak summer but re- grew when intermittent rainfall came during the next season (Pilot demon- stration site at Placer, Bamboo strips can also be used as reinforcing element for deep- seatedinstability. As a material, bamboo has been found to have very high tensilestrength to weight ratio. The tensile strength is about 265-388 Mpa nearingthat of a mild steel at 480 Mpa. In Malaysia Expressway, the use of 6 steep, bamboo reinforcedembankments with side slopes varying from 1:1.2 to 1:0.85 (v:h) alongroabdbank (Fig. 22). To date, no faulting regarding its performance; constructioncost is low than conventional reinforced soil walls. Fig. 22. Construction of a bamboo-reinforced embankment in progress 27
  40. 40. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas The chief drawbacks however are as follows: a) Long-term durability.i.e. prone to attack of fungi, insects, etc. if not treated properly by chemicals; b)variability due to non homogeneity and anisotropy, being a naturally-occurringmaterial (not-manufactured).Potential Hedgerow /Live Pole Species For slope stabilization purpose there are potential plant species withcapacity to reproduce vegetative and utilized as hedgerows or live poles: Africa tulip (Spathodea campanulata) Kapok (Ceiba pentandra L.) Agoho ( Casuarina equisetifolia) Katurai (Sesbania grandiflora) Anabiong (Trema orientalis (Unn.) Blume) Macaranga gigantea Anchoan dilaw (Cassia spectabilis Malungai (Moringa oleifera) Bamboo (Bambusa blumeana Schult) Mangium (Acacia mangium) Calliandra (Calliandra tetragona) Mulberry (Morus alba L.) Calliandra calothyrsus Mulberry (Morus alba L.) Dapdap (Erythrina Orientalis Unn) Narra (Pterocarpus indicus) Datiles (Muntingia calabura L.) Narra (Pterocarpus indicus) Dita (Alstonia scholaris L.) Neem (Azadirachta indica A. Juse) Falcata (Paraserianthes falcataria) Rensonii ( Desmodium rensonii ) Flemingia (Flemingia congesta), Sunflower (Tithonia diversifolia). Flemingia (Flemingia macrophylla) Teak (Tectona grandis Unn) Giant Ipil-ipil ( Leucaena diversifolia) Teak (Tectona grandis Unn) Guava (Psidium guajava J) Tubang-bakod (Jatropha curcas L.) Gubas (Endospermum peltatum) Tubang-bakod (Jatropha curcas L.) Ilang-ilang (Cananga odorata Lam) Vetiver (Vetiveria zizanoides) India Bitongol (Flacourtia indica (Burm.f) Yellow dapdap (Erythrina Merr) variagata) Ipil-ipil (Leucaena leucocephala) Yemane (Gmelina arborea) Kakawate (Gliricidia sepium (Jacq) Walp).BIOREMEDIATION MEASURESFinding Plants with Bioremediation Potential One major task of mining industries is the management of its miningwastes. Bioremediation is an environment-friendly technology that uses thenatural properties of plants and microbes to reduce, if not eliminate, harmfuleffects of hazardous wastes in an area.28
  41. 41. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Phytoremediation is the ability of plants to extract, detoxify, and/orsequester environmental pollutants from soil and water. It is one of thetechnologies that use green plants to remove pollutants from the environmentand render toxic wastes harmless to living organisms. Phytostabilization of heavy metals is also termed in place inactivationor phytorestoration. There are different types of phytoremediation techniquethat involve stabilizing heavy metals with green plants in contaminated soils, asfollows:Types of Metal Phytoremediation (1) phytostabilization- in which plants stabilize the pollutants in soils, thus rendering them harmless; (2 phytofiltration or rhizofiltration- in which plant roots grown in aerated water, precipitate and concentrate toxic metals from polluted effluents; (3 phytovolatilization-in which plants extract volatile metals (e.g., Hg and Se) from soil and volatilize them from the foliage; and (4) phytoextraction- in which heavy metal hyperaccumulators, high-biomass, metal-accumulating plants and appropriate soil amendments are used to transport and concentrate metals from the soil into the above–ground shoots, which are harvested with conventional agricultural methods.Hyper-accumulators: Are plants species that possess the ability to extractelements from the soil and concentrate them in the easily harvested plantstems, shoots or leaves. Some of the identified species are:Thlaspi caerulescens (Alpine pennycress) This plant belongs to the weedy member of the broccoli and cabbage family. It thrives in soils with high levels of zinc and cadmium. This is because the plant possesses genes that regulate the amount of metals taken up by the roots from the soil and deposit these elements in other parts of the plant (Fig. 23). Fig. 23. Morphological characteristic features of Thlaspi plant. 29
  42. 42. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasStackhousia tyronii (Sunflower) A hyper-accumulator plant that can provide a cheap and ‘green’ method of cleaning contaminated agricultural and industrial sites. This plant can also be used to clean pastures and croplands contaminated by heavy metals from fertilizer and industrial pollution (Fig. 24).The study deals on how S. tyronii takes up metal elements from the soil and howFig. 24. Sunflower is easily available species the plant can survive in a toxic condition for propogation. considering that 4% of its leaf dry-weight is pure nickel metal. It explained further thatimmediately after the nickel is absorbed, the plant root detoxify it by forming anorgano-metallic complex.Pteris vittata (Braken fern) Braken fern soaks up ar-senic with staggering efficiency,i.e. 200 times higher in the fernthan the concentrations incontaminated soils where it wasgrowing (Fig. 25). In greenhousetests using soil artificially infusedwith arsenic, arsenicconcentrations in the fern’s frondshave reached 22,630 ppm (2.3% of Fig. 25. Braken fern possess dark green large, longthe plant comprise arsenic). leaflets compared to other ferns. Many other ferns were identified pioneer species in mining areas (Fig.26.) They were observed verdant and persistently growing in its rocky sites andwere acclimatized for a long time in the area. Nitrogen-fixing plants are most suited to be planted in barren miningand volcanic ash laden areas. They have the capability to draw freely nitrogenfrom the atmosphere through the aid of nitrogen-fixing organisms (Rhizobiumand Frankia). They survive and grow normally with lesser fertilizer input. Someof these are:30
  43. 43. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas Narra (Pterocarpus indicus) Yemane (Gmelina arborea) Agoho ( Casuarina equisetifolia) Ipil-ipil (Leucaena leucocephala) Kakawate (Gliricidia sepium (Jacq) Giant Ipil-ipil ( Leucaena diversifolia) Walp). Ipil-ipil (Leucaena leucocephala) Anabiong (Trema orientalis (Unn.) Flemingia (Flemingia macrophylla) Blume) Flemingia (Flemingia congesta), Falcata (Paraserianthes falcataria) Rensonii ( Desmodium rensonii ) Mangium (Acacia mangium) Calliandra (Calliandra tetragona) Dapdap (Erythrina orientalis) Calliandra calothyrsus Yellow dapdap (Erythrina variagata) Anchoan dilaw (Cassia spectabilis Kakawate (Gliricidia sepium) Ferns Katurai (Sesbania grandiflora) Fig. 26. Various varieties of ferns consistently thriving in almost all mined out and mine spoils throughout the country.Ferns are symbiotically–associated with Anabaena a nitrogen-fixingmicroorganism. Its persistence in these sub-marginal conditions can beaccounted to its ability to draw nitrogen from the atmosphere. Hibiscus cannabinus L. (Kenaf) and Brassica napus L. (Canola) werefound to be both effective in detoxifying soil and water contaminated withselenium. These species were used to do biological clean-up of soils and water.Kenaf also provides mats for soil erosion control while grass seeding and padswere used to sanitize chemical and oil spills.Mycorrhiza, a Symbiotic Microorganism with Phytoremediation Potential There are more than 500 known species of endomycorrhiza. Fig. 27shows various spores of various species. Mycorrhizal fungi have anextraordinary capacity for growing, dispersing and surviving stress periods.These abilities make them highly successful organisms despite their dependenceon plant organism for growth and reproduction. With its multifunctionalphysiological capability, it can assist plants to cope up with the countlessenvironmental stresses, as follows: 31
  44. 44. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden Areas • water stress • nutrient stress ( pH, N, P nutrient, other micronutrients) • salt stress • toxic/heavy metals • water • aeration • soil structure problems • other biotic factors such as pathogens • atmospheric pollutants • elevated carbon dioxide It has been the realization that mycorrhiza has exclusion mechanismsi.e. it does not bring to its above-ground parts high levels of arsenic, cadmium,chromium and mercury hence it can be a material for phytoremediation. Heavymetal levels can be gradually reduced in the contaminated sites and can bedisposed off safely elsewhere with use of this biofertilizer. Fig. 27 explains forthe plant physiological responses to inoculation. How the micro symbiont mycorrhiza help respond to plant metal toxicity Fig.27. Mechanisms of how mycorrhiza help respond to Better soil exploration metal toxicity. - Improved root growth Heavy metals - Changed root structure accumulated in - Proteoid roots hyphae are not passed to host Differences in P extraction (EXCLUSION - Phosphate solubilization MECHANISM) - Phosphatase production Phytochelatins Modification of rhizosphere vacuolar - Rhizosphere acidification accumulation citric acid, piscidic acid or proton excretion - Glomalin production In the mine waste area of Antamok, Benguet, positive responses tomycorrhizal inoculation were found in outplanted agoho (Casuarinaequisetifolia) and batino (Alstonia macrophylla) (Fig. 28 and 29). Fig. 28. Robust batino plant in the mine waste dump site.32
  45. 45. Compendium of Rehabilitation Strategies for Mining and Volcanic Debris-Laden AreasFig. 29. Comparative growth performance of Agoho (Casuarina equisetifolia) in mine waste areas of Itogon, Benguet. Recently, species like Tubang bakod (Jatropha curcas) using mycorrhizahave enhanced survival rate even under harsh conditions. The good news is that a mycorrhizal type called vesicular-arbuscularmycorrhiza can infect almost all vascular plants, hence it will have wideapplicability (Fig. 30). Also, the microorganism works in marginal, degradedenvironment. Fig. 30. Spores of vesicular–arbuscular (VA) mycorrhiza Glomus sp. Mycorrhiza has been identified as a major player in removing of heavy metals in soils like the mine waste areas. ERDB has started producing VA mycorrhiza (endomycorrhiza) as pureinoculants for reforestation, agroforestry and coastal rehabilitation since 2000.It is producing more mycorrhiza from various provenances inoculants to betested in mine waste areas. A mycorrhizal seedling produces 8 times as much root and hyphalsurface than ordinary uninoculated plants, absorbs 3 times more nutrients andwater from the soil, and is drought-resistant and disease-resistant than normalplants, significantly greater survival, growth and yield, increased quality ofseedlings under stressed field conditions. 33

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