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Media / Application stories / Atlas Copco CDM75E Drilling Rig at Antaibao Coal Mine

Atlas Copco CDM75E Drilling Rig at Antaibao Coal Mine

2012-02-02

Pingshuo open-pit coal mineis located in Shuozhou, Shanxi Province, China and belongs to China National Coal Group Corp. It is one of the largest open-pit coal mines and a major coal production base in China.The mine has an exploration area Pingshuo Coal Co. Ltd. formally started the operation of Antaibao mining area. At early stages the annual coal output of the mining area was 15 million tons. Today, the output has exceeded 20 million tons.
 
At Pingshuo open-pit coal mine, coal mining is highly mechanized. In the past, Atlas Copco rotary drilling rigs were mainly used in the mining, including DMH, DML, DM50 and DM25-SP series. Atlas Copco keeps launching new models as the demands for large rotary drill rigs in China have been increasing. Among them, CDM75E, which was specially customized for the China market and upgraded on the basis of mature US models, has been successfully assembled in our Nanjing facility. The first CDM75E assembled in Nanjing has been delivered to Antaibao mining area and so far its operation has been good.

Atlas Copco China - DSC04589 MR CDM75E on Antaibo Coal Mine
At Antaibao, the proved reserves of coal are as high as 3 billion tons. Open cut mining method is adopted. The overburden is about 100m thick and the stripping ratio ranges between 5:1 and 6:1. The designed bench height is 15-18m, which is suitable for the operation of power shovels. The coal is mined in three levels. The first level is No. 4 coal seam, the second is No. 9 coal seam, and the third is No. 11 coal seam. Blastholes drilled by CDM75E are arranged in a triangular pattern with an interval of 8*8m. Sometimes hole-to-hole intervals may be adjusted according to actual rock hardness.

These holes have a maximum diameter of 250mm and a depth of 18m and all of them are vertical holes. As a major large-diameter drilling rig, CDM75E is suitable for large scale blasthole drilling. After three months of operation, CDM75E has worked for 170 hours and the net length of hole drilling amounted to about 150,000m. The rig works for two shifts every day, 6 hours per shift, and drills 4 holes per hour. The comprehensive rate of hole drilling is 70-90m per hour. The system pressure of the rig is 65psi. A drilling rig can drill 25,000m in one month. The power shovel used in the area has a capacity of 49m3 and the truck has a carrying capacity of 290 tons.

From the first Atlas Copco drilling rig imported into Antaibao 25 years ago, the mine now has 23 Atlas Copco drilling rigs and 2 domestically manufactured rigs. Compared with drilling rigs made in China, “Atlas Copco’s equipment has reliable quality, with sturdy and durable walking mechanisms. The rig is made from good materials and has high availability and high rate of penetration,” said Mr. Qiao Yu, Manager of Drilling Rig Workshop, Pingshuo Open-Pit Equipment Maintenance Center. “The electrically driven CDM75E has lower failure rate than those driven by diesel engines.”
 
Shuozhou, Shanxi, located in plateau area, is characterized by dry climate with sandy winds. This brings higher requirements to the equipment. “So far Atlas Copco DMH90 and DM25 drilling rigs have been in use here for more than 20 years. They are excellent and reliable and adapt very well to the environment here,” said Qiao.

Customization

CDM75E rotary drilling rig is the latest Atlas Copco model optimized on the basis of mature models and customized for the China market. The rig is equipped with imported roller cone bit and drilling pipes. The service life of the bit is 20,000-30,000m. The explosives are ammonium nitrate and instantaneous detonators.
 
The rig is equipped with imported tailor made 515 kW (700 HP) motor
or 563 kW (755 HP) diesel engine as its main source of power, and 2 variable displacement main pumps and 1 fixed displacement auxiliary triplex vane pump. The main pump adopts the latest design and works in electric control mode, in which the pump displacement may become infinitely variable through the change of electric current, so the drilling rig can maintain continuously smooth operation.

The rig is equipped with 51 m3/min large capacity compressor, which provides vigorous support for mining under the thin air condition at mountainous regions. Besides the model with electric motor drive, Atlas Copco also supplies the model with diesel engine drive and offers the option of low or high pressure compressors to match cone bit and DTH drilling in different mines.

CDM75E integrates the patented technology of mono-cylinder tackle pulley drive system and the hydraulic regeneration system so it not only has sufficient feeding force but also ensures sufficiently quick penetration rate. It saves the time of drill pipe connection and replacement and improves drilling productivity. Under the drive of high oil pressure from two main pumps, the drilling rig generates 334 kN downward pressure and 11,788 N·m torque and makes it very easy to drill holes on the work surfaces. CDM75E is also equipped with multi pass rig and can drill as deep as 53m through the pipe changing operation of carrousel for four 10.7m-long pipes.

The major task of CDM75E at Pingshuo is to drill blastholes in hard rocks at high benches. The job is not easy. The scheme requires that 30m-deep and 250mm-in-diameter holes be drilled at the mining site. CDM75E, equipped with heavy-duty motor and large capacity air compressor, outstandingly finishes the job. There is no earth refill inside the holes and the holes have smooth walls. This is because the dust collection system of the rig gives sufficient space for dusts and manual cleaning is not necessary during deep hole drilling. Mr. Wang Tianli, chief foreman of drilling rig maintenance workshop, Pingshuo Coal Mine, said: “as CDM75E rotary drilling rig is really an excellent design, we will always use it to drill deep holes.” This is a high recognition of quality and service of Atlas Copco as well as an honest comment on CDM75E.

Training and Environment Protection

Currently there are more than 3,000 workers in Antaibao mining area. They work in two sections – maintenance and production. In each shift, two workers operate one drilling rig. Atlas Copco provides well-organized training. The training of operators and maintenance personnel started as soon as the CDM75E drilling rig was delivered to the mine. Within one week, operators and maintenance technicians grasped all necessary know-how. Atlas Copco has four resident service engineers at Pingshuo. “We are not experienced in the operation of the new CDM75E and it is difficult for us to solve problems. They give us many helps and instructions. They are able to promptly solve any problem we have. So I feel very satisfied,” said Qiao.

Furthermore, work safety is a high priority in Antaibao mining area and safety training activities are organized among workers. Special attention is given to fire protection of hydraulic drilling rigs. Fire extinguishers must be equipped on drilling rigs. Welding operations must be looked over by additional personnel. The place of welding shall be cleaned after the welding is finished and welding workers shall no leave until the place has been watched over for a while and no danger exists. And wrong startup shall be prevented during maintenance.

The overburden stripped in the mine, which mainly consists of earth and rock and seems useless, can also play a role. After the overburden is dumped at the dumping site, it can be covered with a layer of soil for planting and restoration of local vegetation. The mine has staff members in charge of planting trees and purchase of grass seeds and saplings. “We employ local farmers whose land was requisitioned as workers in the mine. Now we have employed more than 2,000 local farmers and eased local employment pressure, ” said Qiao. In addition, the enormous amount of wastewater generated in coal washing may also go through treatment for being recycled. In water recylcling alone, the mine saves 1 million tons of water per year.

Future Development

In 2009, the total coal production at Pingshuo open-pit coal mine amounted to 86 million tons. Among the output, Antaibao and Anjialing respectively produced over 20 million tons and the three underground mines respectively produced over 15 million tons. The annual output of Pingshuo is expected to reach the 100-million-ton level. Therefore, the mine will continue to update its equipment. As another three CDM75E drilling rigs have been delivered, the mining at Antaibao area and the whole Pingshuo mine will be further mechanized and these rigs are a vigorous support to the goal of making a 100-million-ton coal mine. The successful application of the first CDM75E at Antaibao sets an example of high productivity and low operation cost for Chinese customers and creates another new starting point for the development of Atlas Copco rotary drilling rigs in China.
 

For further information, please contact:
Caroline He
Marketing Communication Specialist
Atlas Copco Mining and Rock Excavation Technique
Phone: +86 10 6528 0517     
e-mail: caroline.he@cn.atlascopco.com

Atlas Copco is an industrial group with world-leading positions in compressors, expanders and air treatment systems, construction and mining equipment, power tools and assembly systems. With innovative products and services, Atlas Copco delivers solutions for sustainable productivity. The company was founded in 1873, is based in Stockholm, Sweden, and has a global reach spanning more than 170 countries. In 2011, Atlas Copco had 37 500 employees and revenues of BSEK 81 (BEUR 9). Learn more at www.atlascopco.com.

Atlas Copco’s Mining and Rock Excavation Technique business area provides equipment for drilling and rock excavation, a complete range of related consumables and service through a global network. The business area innovates for sustainable productivity in surface and underground mining, infrastructure, civil works, well drilling and geotechnical applications. Principal product development and manufacturing units are located in Sweden, the United States, Canada, China and India.