Presentation illustrates safety Management practices followed at deep mechanized Longwall from Planning to operation

1. Safety Management of a
Deep Mechanized Longwall Mine
By
U. Siva Sankar
The Singareni Collieries Company Limited
National Seminar on
Mines Safety Management & Sustainable Mineral Development

2. Introduction
• Longwall Technology is the world over proven safest method for bulk production.
• The Longwall and other connected machines produce lot of heat, noise and dust,
making the working atmosphere vulnerable and unsafe with extended hours of
work.
• Numerous tasks and risks were involved during the installation, operation, and
maintenance and shifting of Longwall equipment as well as other connected
machineries.
• The physiological and mental stress levels in operating such high capacity
machines are also high.
• Ensuring the safety and health of the miners, and equipment safety will be the
prime responsibility in highly mechanized underground mine.
• Safety management is a comprehensive system of management of different
activities by giving priority to various safety aspects of the Mine.

3. Adriyala Longwall Project – Location Plan
PEDDAPALLI
PEDDAPALLI
BHADRADRI KOTHAGUDEM

4. Adriyala Longwall Project
LWP-2 Details:
• Length : 2231m
• Reserves : 3.0Mt
• Face length : 250m
• Depth : 420m to 506m
7.5m dia- 480m depth
return air shaft.
MMV: 400kW, 250m3/ Sec
capacity
Air chilling Plant
Mar riding chair car
system
LWP-1
OC2 workings
Man riding chair
lift system on
RAMP
Trunk belts
Chairlift Systems
Concrete Road
Proposed LWP-3
Bolter Miner
workings

5. Over View of Adriyala Longwall Project
Stock Pile Arrangement ContingencyMine Control Center
Punch Entries 9.3 kms Trunk belts from Face to SILO
Longwall, Belt conveyors, TBS

6. Salient Features of Mine
Total extractable Reserves : 78.597 Mt
Depth of working : 294.0m– 644.0m
Total Mine area : 4.845 Sq. Km.
Seam gradient : 1 in 6 to 1 in 7.8
Gassiness of the Mine : Degree-I
Targeted production : 2.817MTPA
(2.2Mt in 2018-19)
Life of the Mine : 35 years

7. Planning and Design
• Mining at greater depth needs strategic planning and execution to overcome the
operational problems and issues related to mine environment.
• Adriyala Longwall Project in SCCL was planned to operate with high capacity Longwall
unit.
• Since the inception of the project due care was taken to establish the project with
safety.
• International and domestic scientific agencies were involved in planning and
implementation of the project.
1. M/s CSIRO, Australia -for detailed geo-tech studies, Support capacity estimation and
finalization of tech. specification for modern high capacity LW projects .
2. Mr. Andy Rutherford, Australia for formulating Specifications, testing, drawings and
commissioning of LW project.
3. Mr. Russell Firth, Australia, as a Geo-Technical Studies.
4. Additionally various Indian Institutes also associated in scientific studies and
investigations.
• The equipment was designed to suit the mining conditions.
Safety Management Practices

8. Design of LW equipment
• The equipment is custom designed for integration into each
application and considered all aspects of safety, efficiency, reliable
productivity.
• Rigorous proven processes are undertaken to identify hazards to
people and equipment with risks evaluated and controls
implemented as required.
• 3D models are used to check for clearances, roof support tip to
face, shearer elimination into the gates, snake lengths, humps and
swillies on the face to make sure the correct solutions are
implemented in the design to remove unacceptable levels of risk.
Safety Management Practices

9. Design of LW equipment
• Automation - Shearer Initiated Roof Support Advance (SIRSA) with batch control and auto
horizon control.
• Max. production with by optimum utilisation of equipment.
• Max. safety by avoiding of exposure of mine personnel to unsafe and dust-laden areas.
• For automation, communications system has developed between each Longwall product
called the PMC network. The roof supports are PMC-R, coal clearance is PMC-D, shearer is
PMC-S.
• This system allows each piece of equipment to communicate to each other to enable and
enhance safe reliable production.
– If the shearer is cutting and the roof supports are lagging behind, the shearer is slowed by
a command from the roof supports until they catch up, avoiding unsupported roof or,
– if the coal clearance system is running in an overload state due to face slumping for
instance, then a command is sent to the shearer to slow down and then increase again as
the total AFC load reduces.
Safety Management Practices

10. Electricals
• The total connected load of the project is 35MW.
• 11 kV transmission system was introduced in Indian underground coal mine
for the first time. The incoming voltage to the load centre underground is
11kV.
– Auto power factor correction unit was installed for to curtail the wasteful energy
loss.
– XLPE cables were used considering inherent advantages of higher temperature
range and longer insulation life.
– Use of correctly designed HV cable couplers sealed with recommended
compound.
– The armouring at the ends of terminations is carried into the Clamps to provide
Mechanical support to the cable and also to ensure electrical continuity and
mechanical protection for the cables.
– Distance of min 500mm between two cables was ensured during cable laying to
avoid any electromagnetic interference from one another.
Safety Management Practices

11. Electricals
• Following measures were taken in the design of VFDs of Trunk and Gate belt
conveyors to minimize the harmonics:
– In Trunk Belt Conveyors - Phase Shift Transformers with 12-pulse converter at
front end and Filters & Line Reactors were incorporated.
– In Gate Belt Conveyor - AFE (Active Front End) technology was incorporated.
• To provide employees safety with
information and training to create
awareness of the hazards and to promote
safety-related work practices, SHUT DOWN
PROCEDURES are being followed strictly
and LOTO (LOCK OUT AND TAG OUT)
system is being implementing strictly.
Safety Management Practices

12. Transport & Installation of Longwall equipment
• Underground transport and installation:
Total equipment transportation from surface to Longwall face
and installation was done using diesel utility vehicles
supplied by M/s Caterpillar - Australia.
• Approx. 9000 tonnes of equipment was transported by these
vehicles.
• Vehicles used are:
SH 660D (Max load 60 tonnes) - 2No.s
CL-210 (Max. load 10 tonnes) - 2No.s
CL-215 (Max. load 15 tonnes) - 2No.s
SH 150 (50 tonnes) (Chock trailer) - 4No.s
Safety Management Practices

13. Transport & Installation of Longwall equipment
• Risk assessment was done and safe operating procedures were prepared
for each activity and implemented for transport of heavy equipment,
including during face transfer and installation.
– A surface training area was constructed with fencing around the area
and the ‘roadways’ are demarcated so that operators can become
used to operating diesel machinery on the surface within the
constraints of roadways widths etc prior to operating underground.
– As the presence of diesel in underground is a new hazard for the mine,
Operators have been trained on mitigating measures to avoid diesel
fires.
– Vehicle is subjected to braking efficiency on test ramp of 1 in 4
gradient on surface before sending any diesel vehicle with heavy load
belowground.
Safety Management Practices

14. Transport of Longwall equipment
Transport of pump unit with
CL210
Transport of shield with SH150
Shield trailer
Transport of MG Drive and
Shearer with SH660
Safety Management Practices

15. Men transport
• The mine is very extensive and working places extended for a max. length of 5km.
• To reduce human fatigue and for improved work performance, three chair lift
systems (3.25km) from Overburden ramp to dip most working level were installed up
to the nearest point of mine workings.
• Following safety features were provided for improved safety, in addition to the DGMS
permission conditions:
– Interlocking arrangements to all the drive unit stations, return pulley stations
with fencing and gates and with two exits. When the gates are opened the
running drive wheel will stop automatically.
– Indication switch to allow and ensure persons to maintain 15m distance between
chairs at embarking stations.
– Trip Switch to stop chair lift system in the event of return pulley bearing
slackness.
Safety Management Practices

16. 1
2
3
Man Riding Systems
Sl No Location Distance
01 RAMP Chairlift 750m (1 in 6)
02 Surface to 60L
Chairlift
1222m (1 in 5)
03 61L to 84L
Chairlift
1384m (1 in 6)
04 79L chair car 800m
Total 4156m
4
Safety Management Practices

17. Men transport
Mine cruiser:
– A diesel mine cruiser of M/s Bird Machines, South Africa supplied by M/s
Bharat Earth Movers Limited (BEML), India for transport of LW crew.
– The mine cruiser can carry 16 persons
– A maximum gradient of 1 in 4.
– The performance of the Mine cruiser is not satisfactory.
– In view of this, an order was placed on M/s Valley Longwall International,
Australia for 03 nos mine cruisers on hire basis so as to transport the total
mine workmen to the nearest point of Mine workings.
Safety Management Practices

18. Coal conveyance
• 01 belt conveyor in Gate roadway for LW coal conveyance i.e., Gate belt for a length of 3.0km
and 11 belt conveyors with total length of 9.3km for outbye.
• The conveyors being operated from control room through SIEMENS Programmable Logic
Controllers with SCADA system. Pre-start warnings, voice communication through
amplifiers were provided.
• The safety devices like Chute blockage detection device, Belt sway switch, Torn switch,
Motor & Gearbox temperature sensors, Speed & slip sensors were provided.
• Smoke detectors were provided at every drive of trunk belts. The belt will trip automatically
if smoke detects and water will be sprayed with the help of water sprinkling system provided
at drives connected to PLC. Where, auto sprinkling was not functioning manual sprinklers
were also provided.
• Fire fighting water mains with hoses and nozzles arrangement at regular intervals were also
provided along the belts.
Safety Management Practices

19. Ventilation
• Geothermic gradient is about 10C increase per every 69m depth.
• Study was done by ISM, Dhanbad and according to the requirement mine
drivages were developed.
• Mine is accessed by four Punch entries and one shaft.
• Two main fans of 400kW and 15,000 Cu.m/min (One running + One
Redundant) were provided.
• Booster fan for Longwall working and High water gauge fans for
Development headings for facilitating further ventilation.
Safety Management Practices

20. Ventilation
Chilled air supply:
• To provide comfortable conditions at workplace for improved safety,
production & productivity.
• Outsourced air chilling plant of 1624TR was installed at surface entry of PE-
5. From there cooled air is supplied to Longwall face through a dedicated
air way via PE-5 and Longwall Main gate.
• 50Cu.m/sec of air quantity, chilled from ambient with 50 to 75% relative
humidity to 9 0C at discharge point , at the entry of PE-5.
– After commissioning of air chilling
plant and supply of cool air, the
temperature has been brought
down by 3 to 4 0C.
– Efficiency and effectiveness of
men and machinery increased
considerably.
Safety Management Practices

21. Effect of Major horizontal stress on drivages
Strata Control
σH
σH - Major Horizontal stress
σH
Direction
• More guttering
• Roof disturbed
• More convergence
σH
N970 34’ E
Safety Management Practices

22. Strata Control
Effect of Horizontal stress
Safety Management Practices

23. • Mesh is not tight against the roof.
• Allows skin failure of roof
• Delay in bolting cycle
• Labour intensive
• Mesh is tight against the roof
• No skin failure of roof
• Reduced bolting cycle
• Ease of installation
Introduction of weld mesh
Strata Control

24. Resin anchored bulbed cable bolting
• Cable bolts are 6.1m length with 60 tonnes capacity .
• 3 bulbs at the top for 0.9m for resin anchoring.
• 30 tonnes pretensioning
• Post grouting with cement injection for bottom 5m.
• For avoiding standing supports in Gate roadways, cable bolts were
introduced.
Safety Management Practices

25. 8m width Installation roadway
• 8m width installation roadway with coal roof.
• Supported with cable bolts and no vertical supports.
• Successfully widened and installed longwall machinery with diesel equipment.
Roof condition in installation roadway with cable bolting
STRATA CONTROL
Safety Management Practices

26. Strata Control
• Strata Control and Monitoring Plan (SCAMP) was prepared as per CMR 2017
and is being implemented for both extraction and development of LW panels.
• Strata management techniques of roof monitoring within the control of a
formal TARP to ensure that any roof behaviour that was outside the expected
range of the design was recognised early and remediated well before a major
roof collapse was imminent.
• The following secondary roof support zoning for Gate Roadways of LW panel
was used:
– Zone 1: roof has displaced < 30 mm and does not contain obvious visible
signs of significant roof deterioration such as tensile cracks etc.
– Zone 2: roof has displaced between 30 mm and 100 mm and may contain
obvious visible signs of roof deterioration
– Zone 3: roof has displaced > 100 mm such that currently most such areas
already have steel girders installed
Safety Management Practices

27. Strata Control
• A commonly used indicator is that of ‘Longwall Acceleration Position”
(LAP) it being defined as the distance (either outbye or inbye the face)
that the measured rate of roof movement first exceeds 10 mm/week. The
following initial LAP triggers were implemented initially and are being
refined over time as more monitoring data from the ALP becomes
available:
– < 20 m from the face: normal conditions and no response
– 50 m to 20 m: increase inspections of the roof and have remedial support
contingencies available
– > 50 m: conduct a review of roof conditions from the face outbye to 100 m
and immediately consider the need for additional roof support
Safety Management Practices

28. Cavity Filling – ROCSIL foam filling
• ROCSIL FOAM is a 2 component phenolic foam injected using a metering
pump and a mixing gun.
• During the reaction the product expands from 30 to 50 times and polymerizes
to a hard foam.
• At Adriyala cavity filling was done with ROCSIL foam in LWP-2 tail gate
roadway. The material and equipment was procured from M/s Weber
Company, France.
Safety Management Practices

29. Proactive Inertisation - Nitrogen flushing
• Proactive inertisation with Nitrogen flushing in to the working
goaf .
• N2 plant with a capacity of 1200CFM (≈2100cub.m/hr) was installed
• At present in LWP2 flushing is done at installation chamber, 2nd &
3rd seals from face in active Longwall goaf.
• Purity is maintained at + 98%
Safety Management Practices

30. Mine Environmental Monitoring
Tube Bundle System:
• 20 point tube bundle gas monitoring system of M/s SICK
supplied by SIMTARS, Australia is introduced.
• For environmental surveillance at appropriate locations
belowground.
• Sample from return airways to detect the onset of
spontaneous combustion and to determine gas
generation rates, as well as from sealed and active goafs
to determine explosibility, air ingress and potential
spontaneous combustion activity.
• One analyzer room is provided at surface, tubes laid from
analyzer room to underground monitoring locations.
• The data is transmitted through OFC from analyzer room
to control room where, continuous monitoring of gases
(CO, CH4, CO2 & O2) is being done.
Safety Management Practices

31. Overview of the Tube Bundle System
Tube Bundle
Purge Pump
Sample Pump
Point Select /
Filter Panel
Coal Mine Spec.
Gas Analyzer
Sample System
Incl. Filtration,
Flow Control &
Sample Conditioning
PLC
Exhaust
Surface
Operating Software
Remote Access
Control room
Safety Management Practices
• SAFEGAS software for maintaining & visualizing TBS
• Segas software for visualizing gas trends and further analysis
•TARPS will be designed soon based on TBS results and GC results for Longwall Active and
sealed goafs .

32. Trainings
• In view of the mine requirements young qualified workmen & staff were selected
and posted to carry out the work smoothly.
• Multiple teams consisting of officers, supervisors and technicians were trained in
Germany, Australia and China on Longwall mechanization and Diesel vehicles.
• Further training was given to Adriyala team in Mini build on surface for 03 months
and also training on 11 kV equipment was given by Victor, UK.
• In view of the large Underground mine and many new technologies have been
adopted in the project, a training centre was provided specially for Adriyala to
give initial and refresher training to the Longwall employees. Exclusive training
modules for various subjects and training programme at different levels are under
preparation in consultation with OEM.
• Officers and supervisors are being sponsored for different technological trainings
conducted by prestigious Indian institutes.
Safety Management Practices

33. Outsourcing activities
• The two major contracts - Operation & Maintenance contract of LWP No.2 & Mechanised
drivage (50km) of trunk & Gate roadways and other ancillary activities like civil foundation
works, roadway concreting, seals construction, pipe line laying, belt cleaning, surface
transport vehicles, were also outsourced.
• The following safety practices are being maintaining for safety of the contract workmen:
– Only experienced contractors have been awarded the work contracts.
– Ensuring relevant training of workmen w.r.t. training schedule.
– Issued identity cards stating the stating the name of the contractor and the work and its
validity period, indicating status of Vocational Training & Initial Medical Examination.
– Job-related briefings and conducting safety talks at regular intervals.
– Ensuring the statutory requirements and provision.
– Safe operating procedures are prepared and educating the workmen on the
procedures.
– Outsourcing works committee under project officer: Monitoring all the outsourced
activities & ensuring the works to be carried out in accordance with the Statute and SOP.
– Educating the workmen on use of personal protective equipment (PPE).
– Educating the vehicle drivers on salient provisions of traffic rules.
Safety Management Practices

34. Safety Management Plan
• Safety Management Plan (SMP) is prepared as per CMR 2017.
• Risk assessment was done, hazards were identified, control
measures were defined & responsibilities were fixed.
• The first five major Hazards identified are Inundation, Mine
fires, Ground Movement, Spontaneous heating and
emergency response.
• Principle Hazard Safety Management plans were also
prepared for the major identified hazards.
Safety Management Practices

35. Accident analysis - ALP
• For the purpose of analysis of accidents, Frequency Rates for serious &
reportable accidents per 1000 persons employed, Frequency Rates per
3.0Lakhs man shifts and Frequency Rates per Million tonne of production,
Severity Index are calculated and are as follows:
Frequency Rate for Serious, Reportable and 3 Lakhs Man Shifts
(SCCL and Contractual)

36. Accident analysis
Frequency Rate for Million Tonne of coal produced
Severity Index
From the graphs, it is
observed that the frequency
rate (FR) and Severity Index
(SI) are in gradual reducing
trend from construction
phase to production phase.

37. Conclusions
 The mining industry is involved with high risk and hazardous
working environment and further technological advancement in
intensification of production levels is causing increased concern for
safety in this industry.
 ALP is ahead of most of the coal Mines in the introduction of new
technologies and implementation of safety practices.
 Proper Mine design and technology with in-built fail-safe and user
friendly mechanism are the foundation of Mechanised Mines
safety.
 Safety Management Plan, Statute, Established systems and Self
regulation are the four pillars of the Mechanized Mines Safety.

38. Thank You...