Blasthole Drilling in open pit Mining 141

VIETNAM, HA LONG BAY

A world wonder

With its thousands of limestone karst formations that begin in the surroun-ding mountains and continue to the sea where they stand out as lush, dome- shaped islands, Ha Long Bay is rec-ognized as one of the wonders of the world. In those mountains that overlook the bay lies Vietnam’s largest coal reserve.

The coal region in Vietnam is cen- tered in Cam Pha in Quang Ninh pro-vince, one of the two towns of Ha

Long Bay. Geographically the region is 130 kilometers long, varying from 10 to 30 kilometers wide, or approxi-mately 1,300 square kilometers. Reser- ves here total 2.5 billion tonnes of sustainable supply. Last year the re- gion’s 70 or more enterprises produced 43 million tonnes, representing 90 per- cent of the coal burned in Vietnam and 100 percent of the country’s exported coal.

Diverse needs

Atlas Copco supplies the mines of the region with rigs matched to the size of their various pits. With a complete pro-duct line offering a full range of equip-ment, and with a staff of technicians there onsite, Atlas Copco meets the spe- cific needs of each of its customers.

The majority of drilling in the area is performed by its DML and DM45 blasthole drill rigs. A variety of sur-face crawlers, including ROC F7, ROC F6 and ROC L7 CR COPROD drill rigs, work in smaller operations. The following is a look at three mines and

the drilling operations that make them successful.

Dong Bac

Coal Exploration Enterprise-Dong Bac Corporation produces 140,000 tonnes of coal per year running two rigs. The mine has operated drills from several manufacturers but found its greatest success with the Atlas Copco ROC L7 COPROD drill rig because of its availa-bility. Mr. Vu Van Tan, Chief Operator at Dong Bac, says, “The Atlas Copco drill rigs have similar penetration rates with our other rig, but it’s the uptime of the COPROD L7CR that makes it the mine’s most productive rig.”

At this mine the ROC L7CR drills a 165-millimeter (6 ½ inch) hole to depths of approximately 8 meters (26 feet). The 6-meter (20-foot) deep coal seam rests at an angle from the surface, which results in drilling to depths that end at varying degrees along the coal seam. Mr. Tan likes the size and mobil-ity of the ROC L7 and thinks it’s the best rig for this size operation.

Drilling for coal in Vietnam

Coal mining in Ha Long BayCoal production is a vital part of the Vietnamese economy, and the country’s largest field has turned to modern drilling tech-nology to optimize productivity and efficiency. Atlas Copco is wor- king with many of the region’s companies, providing them drill rigs of various sizes to meet their specific excavation needs.

Within the Vietnamese mountains overlooking Ha Long Bay's karst formations lie the country's largest coal reserve.

DrILLING fOr COAL IN VIETNAM

142 Blasthole Drilling in open pit Mining

Nui Beo

Nui Beo Coal Company is a much lar- ger operation working adjacent to the Dong Bac mine. In 2009 the mine pro- duced 5.1 million tonnes of coal using four blasthole drills. Two of those are Atlas Copco diesel-powered rigs.The others are Russian-made electric mo- dels. The mobility and faster pene-tration of Atlas Copco DM45 and DML blasthole rigs significantly out-drill the competitor’s models.

The two Atlas Copco rigs drill 8,500 meters per month, whereas the other two rigs drill only 3,000 meters per month. The mine’s three shifts produce 22 mil-lion tonnes of waste annually from a pit 4 kilometers long by 1.1 kilometers in width. The projected life extends to the year 2015, with a new property already planned and scheduled for development.

Pham Trung Kien, the electro-mech-anical department technical Engineer, oversees the drill fleet for the mine. Of all these drills, Kien likes the DML the most. With its Cat engine, he thinks it offers more power than the DM45, but both are more productive and efficient

than other drills they have operated. Although he has had no major problems with his Atlas Copco drills, he likes the fact that Atlas Copco and Caterpillar have support people in the area to assist if he should need them.

The DML and DM45 blasthole rigs in the area use 230-millimeter (9-inch) Secoroc tricone bits and 7-meter (23-foot) rods. At Nui Beo, operations are currently 100 meters (328 feet) below sea level on 20-meter (60-foot) benches. Drilling is done at an angle of 10 to 20 degrees at an incline of 5 to 10 percent.

Tay Nam Da Mai

In comparison, Tay Nam Da Mai Joint Stock Corporation also operates the DML, currently drilling at bench elevations 40 meters (130 feet) above sea level. The coal seam is about 40 meters below sea level. Benches are 16 meters (52 feet) in depth on a 6 by 5 meter pattern (16 by 20 feet), which is common in this the area.

Measuring 1.8 kilometers long by 1.5 kilometers wide, this mine produces 1 tonne of coal for every 9 to 10 tonnes of waste. It yielded one million tonnes

of coal last year and will produce 1.5 million tonnes this year. Here the DML drills 5,000 to 6,000 meters per month in the mine’s harder rock and 8,000 to 9,000 meters per month in the softer formations, with another 15 years of life at the current production rate.

Mr. Hoa, Deputy Manager Electro Mechanical department says, “I like the durability of the Atlas Copco rigs and their ability to drill more meters.” Because the competitive rigs have less availability and drilling performance is less, “It takes the (competitive rig) a year to drill the same meters the DML will drill in three months.”

Because of the variations in pit size and desired production, the Quang Ninh province is well served by Atlas Copco’s product line, with the DML as a leader in the class.

Acknowledgements

This article first appeared in Atlas Copco Mining & Construction No. 3, 2010. Story and pictures by Scott Ellenbecker.

Ptam Trung Kien, Technical Manager for Nui Beo Coal Company in front of their DM45. Tay Nam Da Mai prefers the DML drill rig.