This document provides an overview of various surface mining methods. It begins by defining surface mining as extracting ore that lies near the surface by removing overburden. It then discusses the history of surface mining and factors to consider for evaluating surface deposits, including geography, legal issues, and economics. Specific surface mining methods covered include placer mining using panning, sluicing, hydraulicking, and dredging, as well as strip mining and open pit mining.
Practical importance of the Room and pillars method; Different applications of the R & P method; R & P in hard rocks; Conditions of deposit for application of R & P in hard rock; R & P equipment in hard-rock; R & P in soft rocks; Conditions of deposit for application of R & P in soft rock; Characteristics of R & P method in non-coal applications; R & P classic;Step mining; Post-pillar mining; Configuring the R & P method in coal; Main design parameters of R & P in coal; dimensions of the galleries; dimensions of the pillars; Mining with or without recovery of pillars; number of front panel; Advantages and Disadvantages; Screws Ceiling; Design of pillars in coal mine
Practical importance of the Room and pillars method; Different applications of the R & P method; R & P in hard rocks; Conditions of deposit for application of R & P in hard rock; R & P equipment in hard-rock; R & P in soft rocks; Conditions of deposit for application of R & P in soft rock; Characteristics of R & P method in non-coal applications; R & P classic;Step mining; Post-pillar mining; Configuring the R & P method in coal; Main design parameters of R & P in coal; dimensions of the galleries; dimensions of the pillars; Mining with or without recovery of pillars; number of front panel; Advantages and Disadvantages; Screws Ceiling; Design of pillars in coal mine
Introduction; Application of Cut-and-Fill (C & F) stoping; The activity cycle of the (C & F) method; Stages of the production cycle of the C & F method; Sequences of extracting ore bodies; Filling in C & F Method; About filling of stopes; Functions of filler; Types of fillers; Advantages and disadvantages of the C & F method
Longwall; Longwall in coal; Longwall in Hard Rock; Sublevel Caving; Characteristics of the ore body and mining method; Development; Production; Equipments Used; Block Caving, Introduction, Historical evolution of the method, Condition deposit; Principles of the method; Methodology of block caving; Basic issues of geomechanical to the black caving method; Caveability;Mine design Block caving; Fragmentation and extraction control; Subsidence associated; Advantages and Disadvantages of Block Caving
Definition of Open pit Mining Parameters, Open pit Mining method, Bench, Open Pit Bench Terminology; Bench height; Cutoff grade; Open Pit Stability, Pit slope, Pit wall stability, Rock strength, Pit Depth, Pit diameter, Water Damage, Strip Ratio, Open-pit mining sequence, Various open-pit and orebody configurations; Ultimate Pit Definition, Manual Design, Computer Methods, Lerchs-Grossman method, Floating cone method; Open pit Optimization, The management of pit optimization, A simple example; The effects of scheduling on the optimal outline ; Optimum production scheduling; Materials handling Ex-Mine; Waste disposal; Dump design; Stability of mine waste dumps; Mine reclamation; Example of Open Pit Mining Methods
Room and Pillar mining method is one of the oldest existing mining methods. This system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars. Usually those room and pillars are uniform size. Pillars may or may not be removed after extraction.
Used for soft as well as hard rock mining and is commonly associated with coal, potash, uranium, and other industrial materials.
As a mining project is developed from conceptual to production phases, there exist a variety of uncertainties and difficulties that affect the operation’s designs and economic value.
A notable design parameter to be taken into account is the factor of dilution.
DILUTION
Planned and Unplanned Dilution
Internal and External Dilution
Primary and Secondary Dilution
Factors of Dilution
Mine Value Diminutions Due to Dilution
ORE RECOVERY
Room and Pillar Example
Ore Dilution & Recovery in Mining
Rate of Extraction
Introduction; Application of Cut-and-Fill (C & F) stoping; The activity cycle of the (C & F) method; Stages of the production cycle of the C & F method; Sequences of extracting ore bodies; Filling in C & F Method; About filling of stopes; Functions of filler; Types of fillers; Advantages and disadvantages of the C & F method
Longwall; Longwall in coal; Longwall in Hard Rock; Sublevel Caving; Characteristics of the ore body and mining method; Development; Production; Equipments Used; Block Caving, Introduction, Historical evolution of the method, Condition deposit; Principles of the method; Methodology of block caving; Basic issues of geomechanical to the black caving method; Caveability;Mine design Block caving; Fragmentation and extraction control; Subsidence associated; Advantages and Disadvantages of Block Caving
Definition of Open pit Mining Parameters, Open pit Mining method, Bench, Open Pit Bench Terminology; Bench height; Cutoff grade; Open Pit Stability, Pit slope, Pit wall stability, Rock strength, Pit Depth, Pit diameter, Water Damage, Strip Ratio, Open-pit mining sequence, Various open-pit and orebody configurations; Ultimate Pit Definition, Manual Design, Computer Methods, Lerchs-Grossman method, Floating cone method; Open pit Optimization, The management of pit optimization, A simple example; The effects of scheduling on the optimal outline ; Optimum production scheduling; Materials handling Ex-Mine; Waste disposal; Dump design; Stability of mine waste dumps; Mine reclamation; Example of Open Pit Mining Methods
Room and Pillar mining method is one of the oldest existing mining methods. This system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars. Usually those room and pillars are uniform size. Pillars may or may not be removed after extraction.
Used for soft as well as hard rock mining and is commonly associated with coal, potash, uranium, and other industrial materials.
As a mining project is developed from conceptual to production phases, there exist a variety of uncertainties and difficulties that affect the operation’s designs and economic value.
A notable design parameter to be taken into account is the factor of dilution.
DILUTION
Planned and Unplanned Dilution
Internal and External Dilution
Primary and Secondary Dilution
Factors of Dilution
Mine Value Diminutions Due to Dilution
ORE RECOVERY
Room and Pillar Example
Ore Dilution & Recovery in Mining
Rate of Extraction
Open Pit Stability Analysis. Cobre Las Cruces is an open pit mine that extracts copper sulphides from the same volcano-sedimentary Paleozoic deposit as the mines of Rio Tinto.
The exploitation is in essence an open pit measuring 1600 m long x 900 m wide x 250 m deep.
Scope Our Open Mining Services
• Engineering studies (from scoping to feasibility)
• Mining context definition and mining methods selection
• Detailed engineering design (mining, materials handling)
• Development and production scheduling
• Equipment supply and manpower requirements
• Operating cost benchmarking and cost modeling
• Open pit to underground transition analysis
• Kinds of controlling and monitoring system
• Risk analysis and safety management
• Operational review and assistance
Deep sea mining is a new frontier for mining engineers. Sea floor holds the potential mineral that are vital for development which is not even explored, the advancement of technology in the time will enable to access reliable infrastructure and methods to extract sea floor without compromising the sustainability and eco friendly.
Ghana is known as one of the best countries where mining takes place but is rather unfortunate that galamsey is taken the center pace to destroy our flamboyant economy where golds and other minerals have been supportive to the economy's progression in the country's revenue. So in respect of that, we did this research to know where precisely the problem of financial short of exporting gold commodities are coming from and how best can it can be solved to continue to generate inflows for the sustainability of the economy because Gold is one of the heavy commodities that greatly support the Ghanaian economy
Open pit mining is the process of mining a near surface deposit by means of a surface pit excavated using one or more horizontal benches.
The term open pit mining is usually used for metallic or non-metallic deposits and sparingly used for bedded deposits like coal.
This lecture provides an overview of the issues influencing dilution in an underground production environment.
The lecture reviews the dilution problem throughout the entire mining process, and provides a rational approach to underground mine design in order to minimize dilution.
The stages contributing to dilution include orebody delineation, design and sequencing, stope development, drilling and blasting, production and mine management issues.
This lecture provides an overview of the issues influencing dilution in an underground production environment.
The lecture reviews the dilution problem throughout the entire mining process, and provides a rational approach to underground mine design in order to minimize dilution.
The stages contributing to dilution include orebody delineation, design and sequencing, stope development, drilling and blasting, production and mine management issues.
Nature of Mineralization
Geological dilution
Mining Methods and Dilution
Underground Mine Design:
Basic Input
Global (Block) Design Issues
Detailed design issues
Geotechnical Monitoring
Parameters Influencing Dilution:
Orebody delineation
Design and sequencing
Stope development
Drilling and blasting
Production stages
Issues for mine management
Drilling Waste Management in Oil & Gas IndustryGloria Yan
Drilling waste management is a hot topic these years with global attention to environmental protection, especially in oil & gas industry. Drilling waste disposal into environment without any treatment is strictly forbidden. So before disposal, a series methods must be introduced to treat the cuttings and make it reach to disposal standard.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
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Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
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Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
2. In this unit, you will learn the various surface mining
methods used to extract ore from near surface
deposits.
3. After completing this unit, you should be able to:
• Understand the geological factors for surface mining
• Understand the engineering factors for surface mining
• Explain what a placer deposit is
•Understand the surface mining methods:
4. What is Surface Mining?
Surface mine A mine in which the ore lies near the
surface and can be extracted by removing
the covering layers of rock and soil.
Almost all surface mining operations are
exposed to the elements and require no
roof support.
5. History
The history of surface mining is
essentially that of mining coal, copper,
and iron ores, and the nonmetallic
minerals - clays, gypsum, phosphate
rock, sand, gravel, and stone.
Changing public policy is exerting
strong pressure favouring a reduction
or elimination of surface mining; and,
since the economic differences between
surface and underground mining for the
remaining mineral resources is
narrowing, this increasing force may
become the deciding factor in
determining the future trend in surface
vs, underground mining.
6. Evaluation of Surface Deposits
The following outline lists the basic factors which must be taken
into account for evaluation of a prospective surface mine :
• Geography
• Legal status of land and mining rights
• Historical, political, and socialogical factors
• Geology
• Mining conditions
• Ore treatment requirements
• Economic analysis
7. Geography
Topography, a function of location, affects cost of
development and operation of a surface mine. Geographic
location establishes
climate.
Location establishes the condition of remoteness from or
proximity to civilization and its developed facilities such
as transportation systems, power supply, labour pool,
manufacturing and supply services, and specialty repair
shops.
8. Legal Status of Land and Mineral Rights
Land and other necessary rights should be checked, such as water
use rights and the ability to acquire auxiliary land for plant site,
roads, tailings disposal ground etc.
Historical, Political and Sociological Factors
It is important to determine the extent and nature of national and
local laws and regulations in regard to conservation, water use,
water and air pollution, tailings disposal, reclaimation, handling of
explosives, taxes, royalities, import duties, mining safety and health
codes, wage and labour conditions, pension requirements, and
unions.
9. Geological
Geological evaluation may
include wide-spaced drilling,
drill-sample logging, testing
and processing, plotting of the
data on maps and crosssections, preparation of
specialized interpretive maps,
calculation of reserves by
grades, calculation of stripping
requirements, groundwater
studies, and economic
analysis.
10. Mining Conditions
The geometry of an ore body and the
topography of the land surface
beneath which the ore body exists
will affect the kind and cost of a
surface mine. The depth and
character of overlying rock and the
physical characteristics of the wall
rock also affect the configuration
and cost of a surface mine.
11. Ore Treatment Requirements
Almost every potential surface mine
must consider some phase of
product upgrading (benefication).
This may vary from a simple
crushing and sizing operation to a
complex operation including
multiple stages of size reduction,
concentration and agglomeration.
In many cases, pilot-scale testing is
deemed advisable.
12. Economic Analysis
In the broadest sense, economic analysis for a surface
mine involves the determination of market value of the
product and all the elements of cost of production.
By subtraction, a margin of profit (or loss) can be
calculated.
Many new surface mines require very high capital
investments. There are 3 commonly used yardsticks to
value investment worth :
•1) degree of necessity,
•2) payback period, and
•3) rate of return.
13. Methods of surface mining can be subdivided into various
classes and subclasses (E. Bohnit, 1992):
14. Placer Mining
Placer deposits are concentrations of heavy minerals,
usually within loose alluvium that can easily be excavated
and washed. Placer minerals such as gold, tin, and tungsten
minerals, are of relatively high value, but the value of the
placer gravel itself may be very low, often less than a dollar
per cubic yard.
For deposits of such low grade to be worked they must be
near water, on or near the surface of the ground, and should
be only loosely consolidated so that drilling and blasting are
not necessary.
Placer mining affects large surface areas for the volume of
material mined, is highly visible and has serious
environmental problems with surface disturbance and
stream pollution.
The bulk of placer mining falls into three groups-- panning
and sluicing / hydraulicking, and dredging.
15. Panning
In recent years, gold panning has become a
popular outdoor recreation. There is excitement
and appeal in panning an occasional nugget or
a few small specks of gold. The remote chance
of discovering a rich pocket somehow missed
by the old timers provides a strong incentive.
In general, far more money is made selling
manuals, maps, equipment, and gas and oil to
these hobbyists than is made from the gold
itself.
16. Sluicing
In SLUICING the placer gravel is shoveled,
along with a stream of water, into the head
of an inclined elongated sluice box with
RIFFLES positioned across the bottom.
These trap the heavy minerals and the
lighter minerals are washed over the top
and out as relatively barren waste.
Sometimes fine gold is trapped as an
amalgam when mercury is placed within the
riffles or on a copper plate at the exit of the
sluice box. The gold in the amalgam is
recovered by retorting off the mercury.
18. Hydraulicking
HYDRAULIC MINING involves directing a
high-pressure stream of water, via a
MONITOR or nozzle, against the base of
the placer bank.
The water caves the bank, disintegrates
the ground and washes the material to
and through sluice boxes, and / or jigs,
and / or tables situated down-slope.
Hydraulic mining totally disturbs large
areas and puts much debris into the
drainage system. Presently,
hydraulicking is used primarily in Third
World countries. It is closely controlled
or prohibited in the U.S.
20. Dredging
Large alluvial deposits are mined by floating
washing plants capable of excavating the
gravel, processing it in the washing plant, and
stacking the tailings away from the dredge
pond.
A Dredge floats in water and digs the gravel by
an endless string of buckets. Coarse material
is screened out and dumped out the back. The
fine material passes into a series of sluices
where the gold in recovered.
21. Dredging
Several types of excavation methods are in use:
DRAGLINE and BACKHOE PLANTS. Dragline
use in placer mining with washing plants is
limited to shallow digging depths. Its bucket is
less controllable on the bottom than the
backhoe, and it is less able to dig into the
bottom to clean up all the ore that may be there.
However, it has the advantage of a longer
reach.
The digging reach of the backhoe extends to as
much as 70 feet below the surface. It has the
advantage of relatively low first cost, excellent
mobility, and an ability to excavate hard
material.
22. Dredging
BUCKET WHEEL HYDRAULIC
DREDGES are becoming more
popular for underwater
excavation, except where a high
content of soft clay exists or
where excessive oversize material
occurs. It is dependent upon
flooded pump openings that
convey the material mined to the
washing plant, and therefore it
cannot work above water level.
Placement of the pump suction is
critical.
23. Dredging
BUCKETLINE DREDGES are
capable of continuous excavation
and are very efficient. They mine,
process, and discard tailings to
waste in one continuous stream.
However, no storage
opportunities exist, and the
stream moves through the
system by the force of gravity.
Buckets, supported by a
LADDER, dig the mine face.
Material moves up the ladder and
dumps into a hopper that feeds
the washing plant. They are
capable of high excavation rates.
Various methods are used to
position the dredge --anchored
by wire ropes or piling (SPUDS)
at the rear of the dredge.
Boulders can cause serious
problems.
24. Dredging
SUCTION CUTTER DREDGES are
similar to the Bucket Wheet Dredge
except the digging device consists
of a series of cutting arms rotating
in a basket about a suction intake.
The rotating arms break up the
bank material, slurrying it so it can
be drawn into the dredge suction. It
has proven to be successful in
mining unconsolidated beach
sands and offshore placers.
25. PLACER MINING COSTS
Operating Costs (1990):
Capital Cost of Bucketline Dredge (1990):
Because large placer deposits can be thoroughly explored before floating a
dredge, such operations can lend themselves to thorough planning, and it
is possible to carry out reclamation as mining progresses at only a slight
increase in operating costs.
26. Strip Mining
When orebodies are flat-lying and
close to surface, it is sometimes
economical to remove the overlying
rock to expose the orebody. The
surface soil is stripped off and
stockpiled for later land reclaimation.
A stripping dragline with a longboom or long reach shovels are
common.
Large-scale continuous bucket
excavators are gaining popularity.
These large scale machines are
designed for high capacity output
and are tremendous in size, highly
productive, and very expensive.
1 Electric drills prepare the overlying
strata for blasting.
2 Removal of broken ore.
3 Removal of broken rock.
4 Extraction of upper ore seam.
5 Removal of upper ore.
29. Open Pit Mining
Although the basic concept of an open pit
is quite simple, the planning required to
develop a large deposit for surface mining
is a very complex and costly undertaking.
At one mine, it may be desirable to plan for
blending variations in the ore so as to
maintain, as nearly as possible, a uniform
feed to the mill. At another operation it may
be desirable to completely separate two
kinds of ore, as for example, a low- grade
deposit where one kind of "oxide" ore must
be treated by acid leach, but a second kind
of "sulfide" ore must be treated by different
methods.
30. Open Pit Mining
The grade and tonnage of material
available will determine how much
waste rock can be stripped, and there
is often an ultimate limit to the pit that
is determined more by the economics
of removing overburden than a
sudden change in the ore deposit
from mineral to non-mineral bearing
material. The ultimate pit limit and the
slope of the pit walls are therefore
determined as much by economics
and engineering as by geological
structure. Material that is relatively
high grade may be left unmined in
some awkward spot extending back
too deeply beneath waste.
31. Open Pit Mining
The typical large open pit mining
operation that has been in
production for 10 years and more is
operating under conditions that
could not possibly have been
foreseen by the original planners of
the mine. Metal prices, machinery,
and milling methods are constantly
changing so that the larger
operations must be periodically
reevaluated, and several have been
completely redeveloped from time to
time as entirely different kinds of
mining and milling operations.
32. Open Pit Mining
Sometimes the preliminary stripping
of the waste overburden is contracted
to firms specializing in earthmoving.
Mining is usually done by trackmounted electric shovels in the large
operations, and by rubber-tired diesel
front-end loaders in the smaller
operations. Scrapers are sometimes
used in special situations.
Large bucket-wheel excavators of the
kind used in European coal mines
have not been applied to metal
mining, because this equipment is
best adapted to softer bedded,
relatively flat-lying strata..
33. Open Pit Mining
Haulage is usually by truck,
although railroads, inclined
rails, and conveyor belts have
been used.
The conveyance unloads
directly into a primary crusher
and crushed material is stored
in coarse ore bins prior to
shipment to the mill.
34. Open Pit Mining
Bench level intervals are to a
large measure determined by
the type of shovel or loader
used, and these are selected
on the basis of the character
of the ore and the manner in
which it breaks upon blasting
and supports itself on the
working face.
35. Open Pit Mining
Blastholes are usually drilled vertically
by self-propelled, track-mounted
pneumatic or rotary drills. Bulk
explosives are loaded in the holes and
large volumes of ore are broken in a
single blast. Sometimes the drill holes
are routinely sampled and assayed to
help plan the position of the shovels in
advance of mining.
Blasthole assay control is especially
desirable when exploration data are
incomplete or lacking as in the case in
the older pits which have long been
mined past the limits of "ore" used in
original planning.
36. Quarrying
QUARRYING or Quarry Mining is usually
restricted to mining dimension stone prismatic blocks of marble, granite,
limestone, sandstone, slate, etc. that are
used for primary construction of buildings
or decorative facing materials for exterior
and interior portions of buildings.
Quarries generally have benches with
vertical faces from a few feet to 200 feet in
height. Blocks are drilled and wedged free
in a highly selective manner using time
consuming and expensive methods.
Planning of the excavation is based
primarily on geological factors such as the
direction and attitude of bedding and joint
systems.
37. Glory Holing
GLORY HOLING involves a mine opening at the surface from which
ore is removed by gravity through raises connected to adit
haulageways beneath, and tramming the ore to the surface. It is
suited to mining on a hillside, and irregular deposits can be mined
without dilution by waste wall rock. Mining can be quite selective
and little waste rock accumulates on the surface. However,
reclamation is difficult.
38. Auger Mining
AUGER MINING refers to a method of
removing coal, clay, phosphate, oilshale, etc. from thin seams exposed in
deep trenches or high-walls in strip
mines.
The auger consists of two principal
pieces. The first is a cutting head,
generally from 1.5 to 8 feet in diameter.
It may be single or multiple. The second
is a prime mover, usually a skid
mounted carriage, providing a mounting
for the engine, drive head, and controls.
As coal arrives at the surface it is
transported via a conveyor belt or a
front-end loader to a waiting truck.
Operations are usually lowcost and highly productive,
but recovery ranges from 40
to 60%. It can be
implemented with relatively
low capital costs.
39. Solution Mining
Heap leaching
Heap leaching is also
used in recovering metals
from their ores.
Bacterial leaching is first
used to oxidize sulphide
minerals. Cyanide solution
is then used to leach the
metals from the mineral
heap.
40. Solution Mining
Basic concept
The theory and practice of leaching are well-developed because
for many years leaching has been used to separate metals from
their ores and to extract sugar from sugar beets. Environmental
engineers have become concerned with leaching more recently
because of the multitude of dumps and landfills that contain
hazardous and toxic wastes. Sometimes the natural breakdown
of a toxic chemical results in another chemical that is even more
toxic. Rain that passes through these materials enters ground
water, lakes, streams, wells, ponds, and the like.
41. Solution Mining
Although many toxic materials have low solubility in water, the
concentrations that are deemed hazardous are also very low.
Furthermore, many toxic compounds are accumulated by living
cells and can be more concentrated inside than outside a cell.
This is why long-term exposure is a serious problem;
encountering a low concentration of a toxic material a few
times may not be dangerous, but having it in your drinking
water day after day and year after year can be deadly.
The main theory of leaching neglects mechanisms for holding
the material on the solid. Although adsorption and ion
exchange can bind materials tightly to solids, we will simplify
the analysis and consider only dissolving a soluble constituent
away from an insoluble solid. An example is removing salt
from sand by extraction with water.
42. Solution Mining
Countercurrent stage wise processes are frequently used in
industrial leaching because they can deliver the highest possible
concentration in the extract and can minimize the amount of
solvent needed. The solvent phase becomes concentrated as it
contacts in a stage wise fashion the increasing solute-rich solid.
The raffinate becomes less concentrated in soluble material as it
moves toward the fresh solvent stage.
'Heap leaching' is a countercurrent process where the solid is in
a stationary heap and the solvent percolates through the solid.
An example is a dump or landfill. This leaching is essentially
countercurrent. In industrial leaching, solvent and solid are
mixed, allowed to approach equilibrium, and the two phases are
separated. Liquid and solids move countercurrently to the
adjacent stages. The solvent phase, called the extract, becomes
more concentrated as it contacts in stagewise fashion the
increasingly solute-rich solid. The raffinate becomes less
concentrated in soluble material as it moves toward the fresh
solvent phase.