Longwall - China & India

Complex problems demand Innovative Solutions… LONGWALL – A trip to China Lolla Sudhakar, Col. Mgr, GDK.10A Incline & Team

Team (from left to right): P. Srinivas, R.V.Rao B.Chakravarthy D.N.Sharma Lolla Sudhakar Taher Basha L.R.C.Reddy MD.Suresh

Presentation Profile
Details of the Visit
Objective
China – Performance highlights
Pingdingshan Coal Company
Geology & Exploration
Infrastructure – Surface
Roadway development
Longwall – Equipment selection & Operation
Safety & Training
Few Facts of China
Things to be implementable
Action Plan

The Objective
Background
Opencastable reserves are depleting fast.
Longwall is the only economically viable option at greater depths & seams with any gradient.
SCCL is in advance stage of introduction of high capacity Longwalls in few mines at first and on a large scale later.
China is the Worlds largest coal producer (2.19 Bt 2006-07) with 95% of coal from underground mines.
Longwall is the prevalent method in China.
A team of executives were selected to visit Chinese mines to study, observe and analyze the systems, equipment, geo-mining conditions, operations, infrastructure, manufacturing and training facilities, etc which can be applied in procuring the high capacity Longwalls suiting to Indian conditions.

Visit Particulars
Total Period - 13 th May to 13 th June 2007
Underground Visits - 11 days
Class room & Visits - 10 days
Mines Visited - Four (No.1, 6, 12 & 13 Mine)
Surface visits include - Manufacturing plants, Training Institutes,
R&D Centers, Regulatory Bodies.

Training Schedule
First Week - Visit to Pingdingshan Coal Company
Study of Geology, Exploration techniques, Reserve Estimation, Mine Planning and development, Rational Equipment selection, Coal Transport Systems, Washeries, Safety Training, Working by Longwall …
Second Week - Production Management, Regulations/ Permissions, Maintenance & Operational Practices, Mine gas treatment, Visit to Training Center, Power Plant…

Training Schedule
Third Week - Roadway Drivage – equipment, Operation & Maintenance, Visit Pingdingshan Coal Mining Machinery Factory…
Fourth Week - Longwall Face shifting – Planning, Operation, Practices, Visit Beijing Coal Mining Machinery Factory, China Coal Research Institute…

China Mineral Map Pingdingshan Coal Mine

China Coal Map Pingdingshan Coal Belt

Chinese Coal Industry
Largest producer of coal in the world.
3rd largest proved coal reserve in world (1,020.2Bt).
Major source of energy
Accounts for around 76% of total energy production in China.
Coal output in 2005 was 2.19 Bt.
Coal output with mechanized machineries up to 1.0Bt.
Coal preparation capacity up to 840Mt.
Expected coal demand is
2.5Bt by 2010 &
2.8 – 3.0 Bt. By 2020.
CHINA COAL PRODUCTION

95% of the coal produced is from underground mines.
Mechanization in key state-owned mines up to 85%.
Mining productivity 16.2 t/man.
Death rate per Mt of coal produced 0.93.
Multiple levels of industrial structure
Key state-owned coal mines: 47.6%
Local state-owned coal mines: 13.6%
Town and village-owned coal mines: 38.8%
Problems and challenges of Chinese coal mines
High-gassy mines in key state-owned mines: 26.8%
Mines with hazards of coal and gas burst: 17.6%
Mines with hazards of spontaneous ignition: 51.3%
Mines with hazards of explosion: 90%
Chinese Coal Industry

Salient features of the mines visited
All the Mines except No-1 Mine have gradient from 20 0 to 30 0 .
The height of extraction varies from 1.5m to 3.3m.
Mining depths from 300 – 900m.
Face lengths from 150 to 260m.
Panel lengths around 1000m
Production capacities of the Mines range from 1.5Mt to 4.0Mt.
There are 2 to 4 Longwall sets (Chinese made) in operation in each Mine one more set as spare. Output per Longwall is 0.8 – 1.0Mt.
All the supports are 2 legged, 1.5m wide with unit controls. Support capacities from 300 to 650T.
Shearers are of All electric type.

Visit to Pingdingshan Coal Company

Location Pingdingshan Coal (Group) Co.Ltd is located in Pingdingshan City, Henan Province, China Pingdingshan City Look at this…

About Pingdingshan Coal Group
It was the first extra large coal base which was prospected, designed and constructed in new China.
The group has three coal fields: Pingdingshan, Ruzhou and Yuzhou.
Its coal-bearing area is 2,374 Km 2 with good quality coking and power coal.
Pingdingshan Coal Group is a large industrial group with coal mining as leading business and integrates coal chemical, electricity, building material, machinery manufacture, mine rescue center and exploration into one.
Its main products are power coal, clean coal, coke, electricity, chemical fertilizer, mine machinery and cement, etc.

The group has 31 production mines with approved production capacity of 31.01 MTPA.
3 mines under construction with designed capacity of 3.60 MTPA.
5 plants for making smelting clean coal.
7 plants for washing power coal with designed total capacity of processing row coal is 15.50 MTPA.
3 self-supply power plants with installed capacity of 85 MW.
3 coking plants with designed production capacity of 1.25MTPA.
2×110 KV substations and 16×35 KV substations.
Non-coal industries include electricity, coal chemical, transportation, building and mechanical manufacture industries.
It has national grade industrial technology center , the national mine rescue center and national class ‘A’ evaluation & consulting center of working safety and hygiene.
About Pingdingshan Coal Group

Pingdingshan Coal Group – Performance

The Pingdingshan coal field

The Pingdingshan Coal fields
Its strike length (east to west) is about 40 Km and width (south to north) is 16 Km, with coal-bearing area of about 650 Km 2 .
Total No. of working mines –19.
Designed production capacity of 22.70 MTPA and approved production capacity of 28.80MT/A.
One mine (Shoushan No.1 mine) is being constructed with designed production capacity of 2.40 MTPA.

The COAL of Pingdingshan coal-field belongs to Permo-Carboniferous period.
Pingdingshan area contains…
10 No. of Coal seams.
high gassiness (2.082 - 8.61 M 3 /T)
well developed faults.
water inrush is 2000~3000 GPM
Coal seam thickness – 0.6 to 18m.
Geology – Pindingshan Coal fields

General Facts China coal 300m/drill/month. Drill is being run on three shift basis. (Ours is also around 300 mt/drill/ month for 2 shift basis) Productivity of Exploration drilling 1500m Maximum Depth of drilling CLASS-1 5 Bhs/Sq.km CLASS-2 10 Bhs/Sq.km CLASS-3 20 Bhs/Sq.km CLASS-4 30 Bhs/Sq.km Spacing of Exploration BHs - Depending on the complexity of deposit. >6200 UHV (K.Cal/kg) Coking coal Coal Type In-situ Coal Origin

GENERAL EXPLORATION PRACTICES IN CHINA Assigned to University. Not done Exploration wing. GEOMODEL of Block No preserving of core samples for long period . No core storage house Core photography, Core storage house, pattern etc. Not so regularly taken. No software is used to study the core further as CSIRO does. A- Type reserves with a grid of- 500x500m (Proved) B -Type reserves with a grid of -1000X1000m (Indicated) C -Type reserves with a grid of -2000X2000m (Inferred) Type OF RESERVES

Emphasis is not given . In-Situ stress measurements No additional BHs are drilled in LW panels for more geological confirmation as SCCL is advised for Adriyala. Additional BHs for Longwall Panels. Recruited separately for the mines Every mine has one mine Geologist Mine Geologists. There are about 112 bhs in the No-12 mine in an area of 24 sq.km. Collected seam correlation of No-12 mine. Borehole observations including Lithology, Descriptions

No 12 mine is having 2000 to 3000 GPM Study of inflow of water They adopt UG mapping techniques to map particularly structural features- joints, cleat etc. Mr.wu Jianyu, Geologist of 12 mine showed the methodology (Similar to SCCL procedures). UG mapping techniques

VISIT TO PINGDINGSHAN WUHUAN INDUSTRIAL COMPANY.
Manufactures various types of drill bits, core lifters, lifter cases, reamer shells etc.
http:// www.pwuhuan.com
The Company presented 3 NQ and 3 BQ size Diamond bits as samples.

VARIOUS TYPES OF DRILL BITS

VISIT TO SINOCOAL INTERNATIONAL ENGINEERING GROUP(SCIEG ) BEIJING
Provided information of various capacities of Drill machines, Pumps, other accessories etc.
h ttp://wwwscieg.com.cn ,

DRILL SITE VISIT
The BH is expected to complete total depth of 1500m, in 5 months.
6 workers are working per shift in 3 shifts are in operation.(Total-18)
Each drill has 5 Management Officers.
1 Team Leader,
1Dy. Team leader,
1 Dy team leader for Safety,
1Geologist.
1 for Material supply.

VIEW OF DRILL SITE

PRESERVATION OF CORE IN BOXES SCCL CHINA

Exploration

INSIDE VIEW OF EXPLRN. CAMP

INFRASTRUCTURE

Bird’s eye view of mine premises

Control room

Coal Handling Plant

Man winding Shaft Ground mounted multi rope Koepe winder

Surface Substation

Transport on mine surface

No.13 Mine – Premises

Surface Coal Transport System

A glimpse of Transport route UG

Development - Roadway Drivage

Development – Roadway drivage
All the trunk roadways are developed in Stone.
Longwall gate roads are driven with Road header supplementing with hydraulic/ pneumatic operated roof bolters.

Development – Roadway drivage

Variants of Tunneling machines 660/1140V 660/1140V 660/1140V Power-supply voltage 45 kW 75 kW 55kW Power of oil pump motor 100 kW 160/80 kW 120kW Power of cutting motor 145 kW 261 kW 190 kW Total power of motor 5.1m 3.0~5.0m 5.0m Cutting width 4.5m 2.4~4.8m 3.75m Cutting height 21 m² 23 m² 9~18m² Road x-section can be excavated 25t 45t 35t Total weight of machine ≤ 55~60MPa ≤ 80MPa ≤ 60MPa Coal, rock cutting strength ±15° ±16° ±16° Climbing ability 260mm 240mm Dinting depth 1.8m 1.8m 1.55m Height of machine body 2.8m 2.9m 2.1m Width of machine body 8.3m 9.0m 8.6m Length of machine body MRH-S100 EBZ-160 EBZ-120 Model of tunneling machine

Roadheader cutting pattern – based on Dip Cutting method with dip angle less than 20 ° and easily spalling off Cutting method of coal seam with dip angle larger than 20 ° and easily spalling off Cutting method for coal seam with high gas and outburst Cutting method in incline coal seam with dip angle larger than 20 ° , large cross section and high gas and outburst

LONGWALL

Longwall - Introduction
China is producing around 1.0BT from Longwalls.
Face lengths varying from 150 to 260m & panel lengths from 2 to 3 Km.
Gradients worked are from 1 in 2 to 1 in 10 (it gives an idea to work Longwalls in Bhupalpalli area) .
One Face – 1.0MT concept.

Long wall mechanisation
1970s development of LW mechanization started
1980s its initial stage was completed
1990s mature stage was reached
1990s-present fast improvement stage
4legs chock shields to 2legged shields
Max. 8000KN in Pingdingshan, 12000KN in other LW faces
Forward thrust ram with single joint
No side alignment rams
Robust side & top shields with 3 rams operations
Base lifting rams
Only IFS Shields
SUPPORTS

AFC
750Kw with two motors
Chain dimension 26mm × 92mm to 34mm × 126mm.
Pan width increased from 764m to 830mm
Trough height increased from 222mm to 324mm.
Speed 1.2 m/s Capacity 1300Te/hr
End discharge
SHEARER
950Kw ,Electric haulage,simplified ranging arm circuits
Improved track bar arrangement
Heavy duty external rams for R/arm lifting,lowering
Haulage speed increase to 15m/min

Shearer Selection Multi motor Shearer Installed power 475 & 930 KW Chainless haulage All electric haulage Voltage – 3300V

Only required Load center for AFC & Shearer are kept on trolley at TG. Similarly, one Load centre for BSL is placed on BSL.
Hydraulics : Hydraulic Pump station including emulsion mixing plant is made available at out-bye to maintain in clean environment . Feed and return lines are fed to the system all along the gate roadway .
As per their experiences for their working condition on a regular basis sub – assemblies are being replaced taking no. of working hours into consideration.
Example:
1. Gearbox with motor replaced once in 6 months.
2. Ranging arm once in 8 months etc.
Failed Sub assemblies are sent to mine workshop for refurbishing

BSL
200 kW motor, Length shortened to 20-25m
Light weight crusher 3Te
No Shield in line to BSL
ELECTRICALs
All indegenised
Transwitches Outbye of Panel
No set of GEBs -LOAD CENTER
Starter (SIVAD)of BSL,AFC in Bottom gate
All ELECTRICALs located in Top gate (Return air)

WORKING OF LONGWALL FACES
the Longwall face are being worked with 4 shifts basis with one maintenance shift and three production shifts.
Each shift is spreaded for 8 hours with 6 hours underground working and 2 hours overlapping
Workmen are hardly spending time at surface for distribution and man power adjustment.
Less percentage of absenteeism recorded in the particularly in LW production crew where leaves also promptly regulated.
Maintenance shift :5AM-1PM /2PM-8PM
Production time schedule

Man Power Organisation in each shift TOTAL 27 Team leader -Incharge of face Dy.team leader -for gas drainage 6

Pattern of cutting
Except for the special situation, Bi-directional cutting is being normally practiced in the LW faces
IFS shields and AFC are advanced behind the shearer
Shearer speed is regulated depending on Methane emission
Face alignment done manually.Surveyor takes offset twice in a week.

face crew is well trained & experienced in roof control techniques rather than depending on Numerical modeling, instruments and computers.
The instruments being used for strata monitoring
3-5 Continuous Graphical pressure recorders in the strategic supports.
No pressure gauges in the leg-circuits
Convergengence stations rarely installed in the gates to know the Roof dilations.
Tell-tale instruments installed during drivages
Strata control Much importance is given to Face retreat

Periodic weightings are reported at 15-20m interval
Wherever, undue geological disturbances encountered there are roof cavities for which special supporting is being done with wooden planks over canopies of Power supports
There were two big cavities in the faces of No12 mine and in No 4 Mine during the visit But the face retreat was not much affected .
No positive set is provided in the circuits.The supports are set manually.
Setting pressure is 26MPa against the yield pressure of
40 MPa in the faces where 600 &800Te supports are deployed.( i.e < 75%)
Strata control…….

Strata control……..
No undue strata problem during the main weighting
The leg pressures increased only at the ends not in the mid zone of the face during weightings
Some of the faces working with 250 m face width have reported loading in the mid face.
The Barrier pillar is 3-6m.
The convergence and divergence due to the effect of adjacent goaf during drivages of the gallery are visualized to be nullified which is highly controvencial from our age old concept.
The roof,floor and sides conditions are very stable with resign capsule bolting having weak roof of coal and mud stone in this coal field.
Cable bolting and installation of arches were done wherever required during drivages itself.

Oblique face or Staggering the bottom gate
Creep control
Stability of Gate end supports : are being ensured to restrict anti tilting of gate end supports
Support setting : is being taken further care whenever there is acute creep control problem to avoid skidding of Power supports towards dip.

Loose Coal: Special care is being taken not to
advance the supports on loose ground by keeping the face cleaned.
OC prop at bottom drive end: The bottom gate AFC drive is being advanced with the help of an OC prop anchored to the dip side barrier to restrict its movement.
AFC advance: For effective control on antiskid, It is practiced to advance the Supports and AFC from dip to rise.To enable this ,the Supports are advanced in group from dip to rise when cutting done from topgate to bottomgate
Provision to change the position of the Clevis pin: There are three slot holes given in the Clevis connecting to AFC in the Power roof Supports.The position of the slot can be adjusted depending upon the movement of creep

Use of Side shields : The side alignment rams are not provided in the recently developed Supports, instead of that Side shields are effectively utilized for squaring the supports to make them perpendicular to face avoiding tilting of supports
Direct action of CA rams and Elimination of two many joints : The reverse trust ram design modified to forward thrust ram and rear relay bar,front relay bars have been integrated to single piece which has lot of improvement in creep control

Capacity up to 3500 ton /hour AFC

Crusher Stage Loader

Power pack Selection Power pack Pumps 315LPM / 400LPM 200KW / 250 KW Motors 2500 L / 3200 L Tank Capacity NB31.5 Feed / NB 50 Return

Gate Belt + Trunk Belt

LONGWALL - SALVAGE

Longwall salvage
No buttress supports
Wooden cogs,props erected by removing alternate one
Pulling of line supports,turning is done by 40HP slow speed Compact haulers
supports are loaded onto trolley lifting station.
Rope direction is changed to necessary angle using pulleys anchored to roof
8 supports/shift achieved in recent salvage in No12 mine
800Te supports dismantled,transported and assembled near face dip of new face
Face widening done with RHs( 7m/270m) erecting Props at center at a time.
Max salvage period is 45days ( not relevant with spare LW package)

Cross section of LW face under Installation

Supporting at the Longwall face Cross section of Longwall face under withdrawal of supports – Supporting method. Wooden Log Mesh Wooden sleepers Wooden prop Wooden props

Loading of supports Ramp Trolley Hauler - loading Winch

Withdrawal of supports Plan View of Longwall face under withdrawal of supports TG MG Powered Supports Hauler - marching Hauler - loading Loading Ramp Hauler -turning Wooden cogs Out-bye T/p

Transportation of Supports
Method of loading and fixing of support:
The support is disassembled into three parts, i.e., canopy, waste shield and base. These three parts are transported to the special assemble workshop (u/g) and after assembly are transported as a unit to the Longwall face.
Base Loading Canopy loading Goaf shield loading Loading complete support

INFRASTRUCTURE – U/G

Underground roadway

Water barriers in underground

Belt Man riding system

Safety - Underground

Mines safety monitoring & Communication technology

Mobile Communication System in Underground

Nitrogen Fire extinguishing equipments for coal mines

SAFETY & TRAINING

Employee Training
Employee Training & Education Policy
Strict Mine Working Permit System.
Coal Mine Safety Technology Training.
Job Skill Training.
Basic Knowledge Training.

Employee Training
The Pingdingshan vocation education college
Supported by labor department and Coal Administration Bureau of Henan Province.
Responsible for all sorts of training for Pingdingshan Coal Group.
22 professional courses for Mining and 19 Professional courses for other industry.
About 5000 employees are trained per year.
We may adopt local Engineering collages to take care of VTC role with a Nodal officer from SCCL.

Vocational Training Centre

Vocational Training Centre – Class room

TECHNOLOGICAL DEVELOPMENTS (CHINA)

China has developed its own mining technologies suitable for its geological conditions.
Independently developed and manufactured large scale mining/ tunneling/ transporting/ supporting equipments.
China has developed related technology of coal preparation & processing / coal chemical technologies / coal liquefaction/ gasification / multiple production / CBM/ CMM.
Complete LW package has been exported to USA, Russia, India,Turkey, & Vietnam.
Aolirelasji Mine, Russia (2006), achieved 12000 ton/day max.
Technological development in China

Technological development in China AFC -- 400,500,750 kW Totally enclosed type 34mmX126mm twin inboard chain, pan width- 764mm & 830mm, trough height-324mm Haulage capacity – >1000 - 1500 t/h AFC -- 180, 220, 264,320,500 KW Bottom open type, 26mmX92mm twin inboard chain, pan width- 630mm, trough height-222mm Haulage capacity – upto 1000 t/h Multi motor Shearer Installed power475;930 KW Chainless haulage All electric haulage Voltage – 3300V Single Electric Motor Shearer Installed power 150;200;375 KW Anchor chain to chainless haulage Hydraulic haulage Voltage upto 1140 V 2-Legged / 4-Legged Chock shields High flow rate hydraulic system 6400 KN Yield load capacity 4-Legged Chock shields Low flow rate Hydraulic system 2000 KN Yield load capacity Manufacturing fully mechanized equipments with continuous upgradation by planning and research (Mature stage) Development of domestic equipment & technology (Basic mature stage) Imported Set of Equipment Current stage (End-1990s to Present) Middle Stage (Mid-1980s to Mid-1990s) Initial Stage (Mid-1970s to Mid-1980s)

Manufacturing capabilities

Technological development in China Power Support height 0.6 to 6.5 m

Technological development in China LTCC 2-Legged / 4-Legged Chock shields High flow rate hydraulic system 6400 KN Yield load capacity

Technological development in China State of art Testing Facilities

Technological development in China Advanced Manufacturing Facilities

What we learnt from the China Trip …

Notable Points
Commitment & Discipline

Things to be implemented
Pump & sub-station .

Track line & Slow speed hauler.

Systematic Cable anchoring
CHINA GDK-10A

House keeping - Underground

Underground transport with Diesel vehicle

Usage of dome washers for bolting with Resign capsules.

Lamp Room

Existing Exploration should be extended from 600m to 900m depth.
Existing drill capacities from 600m needs to be increased.
Each drill site should be strengthened with the sufficient man power i.e. 6 workers/shift, 5 Officers per drill site.
Block GR should be revised after every 8-10 yrs of opening of the mine as done in China.
One geologist should be posted to each mine.
Geotechnical wing should be strengthened by-
Establishing modern Rock Mechanics laboratory.
Recruitment of geologists with Geotechnical specialization.

Things to be implemented-Immediate
Resin capsules for bolting.
Pipelines in sides.
Improvement in Lighting.
Hauler house, Pump House & sub station
Surface buildings.
Mine dress.
Straightness of face (rope).
Spraying system.

Things to be implemented -Long term
As a nation as a company and as an individual we have to Think big & Plan big
200% commitment at Mine level. 400% at higher level.
Change in concept from “ monitoring for control to monitoring for assistance as done in china”
They plan big mine. They develop large infrastructure keeping in mind future requirements to match with the pace of technological development and increasing demand.

1.Trunks development in stone roof
2. More number of deep shafts for future ventilation
3. Adequate number of sub assemblies.
4. High capacity equipment-350LPM Power pack,Electic shearer,Afc and Belts.
5. Revolution in bolting
6. Use of Cell phones in Underground
Things to be implemented -Long term

One mine like GDK10A has to be chosen as a model mine to adopt some good systems and implement the ideas for transformation.
Some more people (workmen, supervisor, technician, workmen representative and officers) are to be sent to China to understand the positive development and labour laws in China.
The classroom lectures can be minimized and on job training & practical classes has to be maximized.

Certain Chinese items like sprayers; belting jointing machines are to be imported and avenues for its fabrication in our workshop have to be explored.
To achieve the production levels of open cast mine from underground mine more longwall mine has to be planned and opened. One or two mine of Bhoopalpally where UG mining is inevitable can be selected and these mine can be transformed as “ Corporate Mines” after incorporating the systems followed in China with little alteration to suit to our socio-economic condition.

The mines visited by the team are steeper than any of the SCCL mines. They are running Longwalls successfully with good records of accomplishment of consistent production. Thus, it is the time to shed inhibitions of planning Mega LW in steep mines of Bhoopalpally.
“ WE CAN RUN STEEP SEAM LONGWALL ”

Chinese Package –with less sophistication
One Panel – 1.0 MTPA Concept.
With adequate sub -assemblies..
may be tried in SK and Bhupalpalli
Australian Package –
One Panel – 2.0 MTPA concept.
Highly sophisticated equipments .
Introduction of LW’s in SCCL – Options…

Plantation of trees/trunks.

THANK ‘U’

Longwall - China & India

by Venkat Ramana Rao M

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Longwall - China & India Presentation Transcript