Mechanization in Indian Mines - Raising Indian Efficiencies - Quoted in the International Mining (article by John Chadwick)

Dipesh Dipu, a well-known consultant in India and reader of International Mining reports that India’s underground coal mining has stagnated. However, some interesting new technology advances are coming into India's coal mines. In hard rock, progress is being made with interesting drill/load/haul combinations. The potential for mechanisation is very significant.

Dipu notes that underground output has been around 10% (50 Mt/y) of total coal production in India. Most of it has been from the bord & pillar method with recoveries of 30-40%. The level of mechanisation is low in these mines, drilling is done using manual jacklegs, charging manually with cartridges and then coal winning by manual loading onto wagons. The use of side discharge loaders (SDLs) has been inefficient and LHDs are rare. “They have been used in some cases with wagon loading or conveyors,” he explains. “Continuous miners have been used mostly for de-pillaring and have been considered to give reasonable production. Most [underground] Indian coal mines have capacities lower than 1 Mt/y.”

“Longwall mining has been successful in only a few projects, mostly in Singareni Collieries (Godavari basin coalfields), which are low in gas and have relatively uniform strata. The key parameter that determines the safety and viability of any longwall mining project is the roof stability index. In general, mining conditions are expected to be relatively consistent and predictable across the mine site, but may vary significantly between mining blocks. The roofs in typical India coalfields are moderately difficult to cave. There are also significant faulting problems in most Indian coalfields.”

These geological conditions have restricted large scale application of longwall mining in India with projects being restricted to capacities of less than 1 Mt/y to 2 Mt/y. “Singareni Collieries (SCCL) has planned opening a few more longwall panels and has selected a contract miner for one such project.

“Mechanisation in hard rock underground mining has been of a higher degree. Lead and zinc mines in Rajasthan, copper mines in Rajasthan and Jharkhand [and] uranium mines in Jharkhand have performed remarkably well with drill jumbos, LHDs, and skips for ore haulage. Cut and fill and sub-level slicing/caving have been the preferred methods.”

India’s safety statistics are not good. The Directorate-General of Mines Safety reports 59 deaths (18 underground) in coal mines in calendar year 2012, up to August, and 294 serious injuries. Non-coal mines have fared better with 25 deaths (4 underground) and 32 serious injuries.

A new revenue sharing agreement aims to have Singareni Collieries Co (SCCL) start developing up to eight underground coal mines with contract miners. The projects are set to see SCCL’s total annual coal production increase to 53 Mt during the next decade. SCCL has been the leader and had the greatest success in underground coal mining mechanisation.

“We have already started work on two underground mines. Underground mines account for 21% of our total production which we plan to increase to 30% over the next two years,” explains SCCL’s chairperson S Narsing Rao.

SCCL is the country’s second largest coal miner and operates 13 open-pit and 42 underground mines in the southern Godavari River Valley region. This district is estimated to host coal resources of 8,800 Mt along a 350 km belt. SCCL’s target at September 12 for the first six months of the 2012-2013 financial year was 23.3 Mt and it had actually produced 20.75 Mt. The company is concerned about the profitability of its underground operations; with the average cost of production almost three times that of the open pits. “Our endeavour remains to increase profitability from underground mines,” says Rao. “Greater adoption of longwall technology in our new projects should improve profitability for underground coal mining.”

SCCL having 21% of its production from underground mines is significantly higher than the national average of 11%. The company has  started work on the introduction of Asia’s largest longwall project at its Adriyala and Kakatiyakhani coal blocks – to have a total annual capacity of 5.5 Mt. It has started the $190-million construction phase of the Adriyala coal project, in the southern Indian province of Andhra Pradesh. This mine is planned to extract some 2.8 Mt/y of coal from estimated reserves of 54.36 Mt, located in the Karimnagar district of the southern state. “The Adriyala project will adopt underground shaft mining technology to flush out coal and will be Asia’s largest longwall installation,” said Rao. “The Australian government’s Commonwealth Scientific and Industrial Research Organisation has been mandated to advise on technical specification for the project.”

The Adriyala coal project is part of the company’s plan submitted to the Coal Ministry that envisages increasing total annual coal production per year to 57 Mt during India's 12^th Five Year Plan period (2012/17). The entire production from the Adriyala coal mine would be linked to the 2 100 MW Ramagundam thermal power plant operated by India’s largest power producer, NTPC Limited.

New Cat in India

India’s experience with longwall shearing has not been a great success to date. In fact there have been some fairly spectacular failures. However, Caterpillar is confident that its new EL3000, designed “to deliver high production in mid to high seams through smart design and next-generation technology,” can make a success in Indian conditions. One of the first units is going to India.  The EL3000 represents the next generation of Cat shearers. The powerful state-of-the-art control system with Ethernet communications suits the shearer to advanced automation and monitoring, and the design is easily upgraded during rebuilds to take advantage of the latest performance enhancing features. The future- proof design ensures long service life.

The core of the EL3000 is the robust one-piece mainframe that provides durable performance and maximum protection for modular components, but is designed for ease of maintenance. The Jumbotrack® haulage system also delivers high performance and long service life. The innovative two-piece trapping shoe, which attaches the shearer to the haulage rack system, allows easy wear part replacement at any location along the face for maximum uptime.  This shearer mines seams of 2.7 to 5.4 m in height with cutting power of as much as two x 860 kW. A range of cutting motors is available to suit all mining conditions. Haulage motors have power of as much as two x 150 kW and the pump motor has 75 kW to provide a total installed power of more than 2,295 kW. The high level of installed power delivers production capacity of more than 5,000 t/h, Caterpillar says.

A state-of-the-art distributed automation system for the control, monitoring and protection of the shearer has been developed. Its modular design allows it to be configured to meet individual control needs, from basic monitoring and protection to advanced automation and data transmission. The PMC Evo-S control system with state-of-the-art Ethernet communication and backup functionality allows the shearer to be operated even if the overall control system is not functioning. Remote control and diagnosis are possible for all components. VibraGuard is available for condition monitoring on Cat longwall shearers. The system collects data and transfers it to a surface control centre for detailed analysis and evaluation. It enables trained personnel to predict machine component wear, avoid unplanned downtime and set alarms to warn the operator if monitored machine components run the risk of damage. This comprehensive protection promotes long component life by identifying small problems before they become big ones, and it contributes to high shearer availability by reducing unplanned downtime. The PMC system with Ethernet bus offers additional benefits. It results in a vast reduction in wiring and a great increase in flexibility. There are no interfacing problems, as equipment connected to the network only needs to be able to communicate via Internet Protocol. Commissioning, maintenance, upgrades and troubleshooting are much easier and faster, and equipment is self-configuring. The few cables that are used are standard Ethernet cables rather than application-specific cables.

Flameproof housings are no longer required, simplifying installation and speeding up maintenance. A government panel has suggested splitting

CIL or allowing joint venture partners with the state-owned miner to foster competition in the sector. This is one of the key recommendations made by the task force on national security headed by former national security adviser and cabinet secretary Naresh Chandra. The report believes that CIL, being a virtual monopoly under government control, has stifled competition in the coal sector. This has inhibited the raising of efficiencies and modernisation. The panel’s suggestion comes at a time when the country is grappling with a severe shortage of coal that has increased its dependence on imports to fuel power plants. Imports have increased from about 50 Mt/y five years ago to upwards of 140 Mt, with accompanying power shortages. CIL’s Annual Plan 2012-13 aims to achieve coal production of 464.10 Mt and sales of 470 Mt.

High power open pit

For surface mining, Caterpillar is supplying six of its large rope shovels and two draglines to the private coal mining and power generation company, Sasan Power, a subsidiary of Reliance Power. The shovel and dragline fleet is the largest of its kind to be sold to a private company in India, and includes a number of 'firsts'. “We are targeting world-class mining performance and productivity benchmarks,” said Russell Taylor, a mining engineer who is Project Director for Reliance. “We are designing the operation for productivity rates six to seven times greater than the average in India—even as we develop the mines at a faster rate than any others currently underway in India.”

The fleet includes six Cat 7495 HD shovels and two Cat 8200 walking draglines. The draglines, formerly Bucyrus products, will be the first such machines to be delivered with Cat branding and Caterpillar Yellow paint, and they will be the first 8200s with state-of-the-art AC electric direct drive systems. The draglines also will be the largest operating in India—each with a bucket size of 61 m3. The shovels also feature AC electric drive, as do all Cat rope shovels. Each 7495 HD handles a payload of 81 t. Five shovels will be commissioned by the end of the year, and one shovel will be commissioned early next year. The draglines will be commissioned in 2014. All of the machines are going to work in captive mines ramping up to supply about 16 Mt/y of to the new 3,960-MW Sasan Ultra Mega Power Project near Singrauli, Madhya Pradesh. The mines, Moher and Moher Amiohri Extension, will have a production capacity of 20 Mt/y with annual overburden excavation of 80 million m3.

“We are pleased to be a part of developing a world class coal mining operation,” said Robert Foss, Managing Director of mining sales and support for Caterpillar Global Mining in India. “Working with the regional Cat dealer, GMMCO, we already have assembled four shovels and are progressing on schedule to bring the excavating fleet up to full production capacity. We feel that our AC electric shovels and draglines will be the most efficient and productive operating in India.”

Hard rock progress

Sandvik has made key contributions to mechanisation in Indian underground metal mines. Since the UG Hardrock segment of Sandvik was formed in January 2006 it has consistently contributed to increasing productivity in various copper, zinc, gold and uranium mines, be it. One example is the introduction of Sandvik’s first longhole production drill – Solo 5-7C (DL 310) – at Zawar mines of HZL (Hindustan Zinc Ltd) “that soon proved to be a revolution in underground metal mining, says Swastika Mukherjee, Marketing Communication Manager, India Mining APAC. Drill advance “started increasing exponentially. Best achieved figures – 165 m in one shift and 480 m in a day.” Many other mines followed suit and opted for this equipment to increase drilling capacity, Mukherjee reports. “After removing the bottleneck of drilling with Solo, Sandvik introduced a combination of a 17 t loader and 50 t truck for the first time in India for mass production, in 2010.” Again this was to an HZL operation, the SK mine. “LH517 and TH550 combination proved to be the best production machines with consistent performance and less maintenance.”

Atlas Copco too has made achievements with HZL. Earlier this year it received orders valued at over €13 million from HZL. This is one of the largest underground mining contracts for Atlas Copco India. It will deliver a total of 24 machines which includes face drilling rigs, long hole drilling rigs, bolting rig, loaders and trucks. The long hole drilling rigs Simba 1254 and Simba 1354, 15 t loader Scooptram ST1530, 50 t Minetruck MT5020 and the 60 t Minetruck MT6020 mark their maiden entry into the underground mining market in India. The delivery of all these 24 equipment will be completed in 2012.

HZL is a Vedanta Group company, and is the world’s largest integrated producer of zinc, as well as being India’s largest producer of lead and silver. It also operates the world’s largest zinc producing mine - Rampura Agucha – in Rajasthan and has the distinction of being the world’s lowest cost zinc producer. The two companies have been associated for the past 30 years, and the Atlas Copco fleet will be used by HZL for two of its newest underground mining projects at the Kayad and Rampura Agucha mines.

Atlas Copco and the Kayad mines share a long history together where Atlas Copco had sold a Diamec 262 for exploration about ten years ago. The Kayad mine is being developed 9 km from Ajmer in Rajasthan and will produce zinc and lead. Rampura Agucha mine, located 230 km north of Udaipur in Rajasthan, has an annual ore production capacity of 6 Mt from an open pit where Atlas Copco hydraulic DTH rigs already form the backbone of surface drilling operations. Atlas Copco India is now going to support the underground mining operations of Rampura Agucha by supplying high capacity equipment there. There were 2,999 working mines (excluding atomic & minor minerals) located in 21 states reporting production to the Indian Bureau of Mines during 2009-10. Among them, 574 mines were in coal and lignite, 700 in metallic minerals and 1,725 non-metallic mines. There were 770 mines in the public sector and the remaining 2,229 mines were in private sector. The reporting mines were concentrated in 11 major states, namely, Andhra Pradesh, Chhattisgarh, Gujarat, Jharkhand, Karnataka, Madhya Pradesh, Maharashtra, Odisha, Rajasthan, Tamil Nadu and West Bengal. These accounted for 93% of the total reporting mines.

The bureau reported that “optimisation of blast design parameters for mining projects along with monitoring and control of ground vibration, air overpressure and fly rock are needed to solve challenging problems during surface and underground excavations. “Large reserves of good quality coal are locked up in developed bord and pillar workings. NIRM (National Institute of Rock Mechanics) has been making efforts for extraction of coal from difficult seams by designing innovative and modern methods of work. Ground control investigations and systematic strata/support monitoring are essential for safe design of underground mining methods and to validate the designs. Mine Design Department is actively involved in rock mass characterisation, support design for underground/opencast mines and strata monitoring.”

The vision of the Ministry of Mines is “to promote optimal utilisation of India’s mineral resources for its industrial growth and create economic surplus using scientific exploration and sustainable mining practices. “India must ensure best practice technology application across the mining value chain, most prominently in high-tech exploration instruments and underground mining equipment. Faster clearance for technology import and usage needs to be ensured.” IM