Bengalla coal mine

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Bengalla Mining Company has established the Bengalla open cut coal mine, located approximately 4km west of Muswellbrook in the Upper Hunter Valley of New South Wales, Australia.

Bengalla’s history as a project goes back to 1990, when the NSW Government called for expressions of interest from mining companies to develop the coal resource.

Subsequent drilling of exploration holes, technical, commercial and environmental studies took place from 1991 - 1993 and at the end of 1993 the Bengalla Joint Venture was confident enough to go to the NSW Government and apply for a mining lease and make a development application which included lodging of the mine’s Environmental Impact Statement. Following rigorous scrutiny, Bengalla received NSW Government approval for the development and on 27 June 1996 was granted a Mining Lease over the resource.

The Bengalla Joint Venture announced that it had taken the decision to mine its lease area on 2 September 1996 and invested $450 million as part of the construction and development programme.

Bengalla Mine was officially opened in 1999 by the Premier of NSW, the Honourable Bob Carr.

The Owners

The original Bengalla Joint Venture was formed in 1990 with the objective of gaining the exploration rights to the Bengalla Coal Development Area, proving its economic viability and developing and operating a large scale open cut export coal mine based on the resource.

Since 2001 Coal and Allied Industries Limited, a Rio Tinto Group Company has been the manager of the joint venture. Coal & Allied managed mines include Bengalla, Hunter Valley Operations, and Mt Thorley Warkworth.

The current Participants and their interests in the Joint Venture are:

CNA Bengalla Investments Pty Limited: 40%
(a wholly owned subsidiary of Coal & Allied Industries Limited, a Rio Tinto Group Company)
Wesfarmers Bengalla Limited: 40%
(a wholly owned subsidiary of Wesfarmers Limited, a diversified publicly listed resources company based in Western Australia)·
Taipower Bengalla Pty Limited: 10%
(a wholly owned subsidiary of Taiwan Power Company the government owned power generation and distribution utility of Taiwan)·
Mitsui Bengalla Investment Pty Ltd: 10%
(a wholly owned subsidiary of Mitsui Coal Holdings Pty Limited whose parent company is Mitsui & Co. Ltd, one of the leading Japanese trading houses)
The Project

The Mining Lease covers an area of approximately 12 square kilometres (or 1,200 hectares). Coal seams amenable to open cut mining occur in eight correlated coal seams or splits. Bengalla has proved Reserves of over 200Mt and Measured and Indicated Resources of 169Mt. The overburden to coal stripping ratio is in the order of 3 bank cubic metres of waste per run-of-mine tonne of coal.

The coal seams dip to the west, generally at less than 5 degrees. The mining strips for resource removal are aligned approximately north-south, perpendicular to the dip. The coal is highly regarded as a fuel source for electricity generation.

The mine design recognises the need to minimise environmental impacts on the area and to ensure adjacent agricultural land can continue to be productively utilised. For instance, the initial mining strip has been located sufficiently west of the Hunter River and adjacent escarpment to allow adequate room for screening, spoil placement and service and coal transport corridors. There will be no mining of alluvial agricultural land adjacent to the Hunter River.

Another example is the location of the infrastructure area to the southwest of the open cut mining area. This location was chosen as it is further from Muswellbrook township and less exposed.

The construction of the first stage of the mine and facilities was completed in just two years, with the first delivery of coal to the export market made in April 1999.

Since that date over 27 million tonnes of coal has been sold within the domestic and export market. Coal reserves within the current mining lease will continue to support operations beyond 2030 at present production rates. One seam below the open cut may even be suitable for underground mining at a later stage.

Mining continues to proceed westward (away from Muswellbrook) with rehabilitation of mined out areas already having commenced. Hydromulching is used to promote growth soon after reshaping and topsoil spreading. Tree planting is also continuing as part of the mine’s Landscape Plan.

At Bengalla the aim is to return the mined land to at least as productive capacity as it was originally. Opportunities to establish native corridors or new long-term industry on mined land are being explored with the community.

Mine Layout

At Bengalla the coal seams sub crop in a north-south direction and dip gently to the west. The mining strips are designed to be parallel with the sub crop direction and perpendicular to the dip.

Haul trucks transport the coal from the mining face to a coal receival hopper which is presently located on the eastern mine lease. This coal hopper is connected to a 4.5 kilometre overland conveyor that runs back to the main infrastructure area and Coal Handling & Preparation Plant.

Mining Method

A strip mining method is employed at Bengalla Mine. This mining method is commonly used when coal seams are situated close to the surface and in a consistent, flat lying orientation. The process of Strip mining involves the digging of a ‘trench’ to expose the coal seam. These trenches are called Strips. The material removed from the strip (waste) is then placed adjacent to the trench, much like a trench dug to install water pipes. After the coal has been mined from the strip the next strip is dug right next to the previous strip. The waste material from the new strip is then dumped into the previous strip. This process is continued until then end of the mine.

The stripping ratio at Bengalla is low. Roughly 3 cubic meters of waste rock will need to be removed in order to get 1 tonne of coal. A 3:1 strip ratio is less than most other coal mines in the Hunter Valley. This means mining costs are relatively low and less equipment is used, this also helps minimise our impact on the environment.

Before mining can begin, the topsoil is removed and stockpiled so that it can be reused during the rehabilitation process. If possible the topsoil is taken directly to an area which has already been shaped and is ready to be rehabilitated. Once the topsoil has been removed it is necessary to blast the underlying rock in order to break it into a manageable size so that it can be handled by either the dragline or excavators.

The overburden is the waste rock between the topsoil and the top coal seam. At Bengalla a pre-strip fleet consisting of 2 excavators and truck is used to remove the overburden and dump it into the previously mined strip. Once that coal has been mined the interburden, which is the waste rock between two coal seams, is blasted so that it can be removed again by the pre-strip fleet and the next coal seam exposed. This process continues down to the Piercefield coal seam.

After the Piercefield seam has been reached, Bengalla uses a dragline (P&H 9020) to uncover the remaining coal seams. The dragline process sequence at Bengalla is fairly complicated and takes 5 passes to uncover the lowest coal seam. The first pass, which is the Vaux Pass, is done from the high-wall of the mine where the dragline digs the waste and dumps it directly into the previous strip. Once this pass has been completed the dragline steps out onto the Vaux waste and sets up to start the second pass which is the Broonie/Bayswater Pass. The dragline uses the Vaux and Broonie/Bayswater waste to build a pad from where it can uncover the Broonie/Bayswater, the Wynn and Edderton coal all in individual passes.

Trucked waste and washery discard (reject) are placed behind the dragline dump spoils. The washery reject is then capped with a minimum of 5 meters of inert waste material. Once the waste dump reaches its final design limits, it is shaped back to a final slope of 10° and covered with topsoil to be rehabilitated.

Bengalla is using what is recognised to be some of the most modern mining equipment currently available. When ordering equipment Bengalla staff work closely with the suppliers in order to ensure that noise levels for each piece of equipment is less than ever before.

All trucks at Bengalla have been fitted with rear viewing video cameras enabling staff technicians to view the areas being reversed into. This has eliminated the need for reversing beepers on these pieces of equipment.

The Mining equipment at Bengalla includes:

Vehicle
Units

P & H 9020-65B dragline
1

Hitachi EX5500 Excavator
1

Hitachi EX3600 Excavator
1

Hitachi EX3500 Excavator
1

Svedala SKF 50i Drills
2

Hitachi R280 Dump Trucks
12

Hitachi R190 Dump Trucks
4

Caterpillar D11R Dozers
4

Caterpillar D10 Dozer
1

Caterpillar 854G Wheeldozer
1

Volvo A25C Service Truck
1

Hitachi AH400D Truck
1

16H Cat Grader
2

Caterpillar 988F Cable Reeler/ Loader
1

Euclid R90 Water Carts
3


Support vehicles and equipment such as lighting plants, pumps, compressors and light vehicles are acquired or hired as needed for the efficiency of the operation.

All equipment is designed to comply with Bengalla’s noise requirements and specifications for both static and dynamic sound power levels as required for compliance with Bengalla’s consented noise limits at non-company owned residences.

Dragline – P&H Model 9020

Cost
$56 million


Dig Depth
75.5m

Dump Height
64.2m

Shoe Clearance
0.6m

Step Length
2.3m

Weight
5,666t

Boom Length
118.9 m

Boom Angle
39.8 degrees

Bucket Size
64.5 cubic metres

Total horse power
21,000

Tub diameter
22.3 m

Ground Pressure
20.7 psi

Width Across Shoes
32.6 m

Rope Size
95.3mm


The fitting of specially designed noise attenuation equipment has ensured that it is the quietest dragline for its size in the world.

Hitachi Excavator EX3500

Cost
$4.2 million


Engines
Cummins KT38

Horse Power (each)
880HP (1312kW)

Bucket Capacity
20.6 cubic metres

Weight
334t



LeTOURNEAU 1800 FRONT END LOADER

Cost
$5.1million


Engine
Cummins

Horse Power
2000HP (1492kW)

Electric Drive
J-2 D.C. Traction

Bucket Capacity
25 cubic metres

Weight
217t

Lift Height
11.9m

Length
17.83m

Width
9.2m

Height
6.43m

Fuel
3975L

Hydraulics
1419L

Crankcase
204L

Wheel Motors (each)
136L



SVEDALA REEDRILL SK50

Cost
$1.3 million


Engine
3406 316kW (430HP)

Weight
50.4t

Overall Length
9.1m

Length Mast Down
12.7m

Overall Height Up
12.3m

Height Mast Down
4.5m

Overall Width
4.8m

Rotation Speed
0-210 RPM

Torque
9,500 ft-lbs (42,258Nm)

Undercarriage
Caterpillar 330L

Compressor
750CFM @ 125 PSI

Pull Down Pressure
50,000 lbs (22,680kg)

Hoist Capacity
50,000 lbs (22,680kg)

Feed Rate
0-110ft/min (0-33.5m/min)

Hoist Rate 0-110ft/min
(0-33.5m/min)

Stroke
28’-8” (8.74m)

Steel Size
6 ” (158mm)

Bit Size
8” (200-229mm)

Fuel Tank
1750L

Hydraulic Tank
884L

Water Tanks
1200L



Euclid R280 Rear Dump Truck

Cost
$4million


Engine
Cummins QSK60

Horse Power
2700bhp(2013kW)

AC Electric Drive
Siemens

Pay Load
270t

Struck
165 cubic metres

Maximum GMV
463t

Length
14m

Width
8.2m

Height
7.04m empty

Tray Up
14.3m

Loaded
9.5m

Fuel
2838L

Hydraulics
1256L

Crankcase
272L

Wheel Motors (each)
257L



Euclid R190 Rear Dump Truck

Cost
$2.5 million


Engine
Cummins K2000

Horse Power
2000bhp(1492kW)

Electric Drive
GE Statex III

Pay Load
183t

Struck
77.7 cubic metres

Maximum GMV
310t

Length
12m

Width
6.7m

Height
6.3m empty

Tray Up
1.5m

Loaded
8m

Fuel
2838L

Hydraulics
650L

Crankcase
209L

Wheel Motors (each)
39L



Caterpillar D11R Dozer

Cost
$1.6 million


Engine
3508B 634kW (850HP)

Weight
102.3t

Overall Length
10.8 m

Overall Height
4.7m

Blade Semi-U
6.4m

Fuel Tank
1471L

Engine Crankcase
106L

Final Drives (each)
30L

Transmission
344L

Hydraulic System
205L

Roller Frames (each)
95L

Pivot Shaft Comp
51L

Cooling System
231L



Caterpillar 854G

Cost
$1.7 million


Engine
3508B 597kW (800HP)

Base
992G Loader

Weight
99.3t

Overall Length
13.2m

Overall Height
5.6m

Tyres
45/65m wide

Fuel Tank
1347L

Crankcase
100L

Differentials & Final Drives
Front 360L

Rear 245L

Transmission
211L

Hydraulic System
877L

Cooling System
280L



Volvo 25C Service Truck

Cost
$800,000


Engine
Volvo Penta

Horse Power
251HP (187kW)

Gearbox
ZF 5 speed split box

Weight
40.3t

Volumes:


Diesel
12,500L

Coolant
500L

Grease
500kg

Oil
1600kg

Waste Coolant
500L

Waste Oil
500L



Caterpillar 988F

Cost
$1.1million


Engine
3408E

Horse Power
430HP (321kW)

Weight
46t

Length
11m

Fuel Tank
659L

Coolant
175L

Crankcase
42L

Transmission
70L

Diffs & Drives
290L

Hydraulics
235L

Attachments:


Agora Cable Reeler


Straight Edge Bucket
6 cubic metres

Fork Attachment



Euclid R90 Watercart

Cost
$1.2million


Engine
Cummins KT38C

Horse Power
1050 bhp (783kW)

Transmission
6 speed

Maximum GMW
150t

Watertank
80,000L

Foam Tank
250L

Length
10.3m

Width
5.1m

Height
5.6m

Fuel
1003L

Hydraulic
430L

Crankcase
140L

Diffs & Drives
208L

Reference for information:
www.bengallamine.com/pages/intro/index.html
www.coalandallied.com.au/whatwedo/333_bengalla.asp

Reference for location:
maps.bonzle.com/c/a?a=p&x=150.920159852141&y=-3...