Blasts are now past
Keeping up with a demanding production schedule without compromising on safety is crucial for the large Ezhuang mine in eastern China. That’s why the mine is looking for new ways to handle its exceptionally hard rock without resorting to heavy blasting, which raises the risk of incidents and injuries.
Piles of coal the size of army tents lie on the edge of the streets in front of small businesses in Laiwu, a city of 1 million people in China’s coastal province of Shandong. Protected from the wind and rain by large tarpaulins, this fuel ends up in small stoves, boilers and furnaces.
About Shandong Energy Group Co. Ltd.
The company: A state-owned coal mining enterprise headquartered in Jinan, Shandong province, China.
Background: One of China’s largest coal companies, created in March 2011 by the merger of six existing coal mining companies, including the Xinwen Mining Group.
Coal operations: Coal coking, coal to gas, coal to olefins and coal to alcohol ether. In addition, Shandong Energy Group’s equipment manufacturing subsidiary produces coal machinery and medical equipment.
Output: Mined 108.2 million tonnes of coal in 2011 and 120 million tonnes in 2012. The company aims to bring coal production up to 200 million tonnes.
“The coal in the streets doesn’t come from us,” says a manager at Ezhuang Coal Mine, a large state-owned enterprise beneath Laiwu. “It is probably from some small local colliery outside of the city.”
Huge reserves of thermal and metallurgical coal sit directly beneath the city. Ezhuang is an old mine that has been in operation for decades. Its walled compound looks more like a school than an industrial operation. Inside the compound on summer afternoons the cicadas sing in the old trees. The mine’s rich seams make it profitable even today. However, its design dates back to the days of blast mining.
To increase safety and profitability in recent years, its owner, Xinwen Mining Group – a part of China’s massive Shandong Energy Group Co. Ltd. – has encouraged Ezhuang to mechanize operations. As the mine required powerful equipment to cut hard rock, Sandvik suggested its MR340 roadheader, a machine with an established record for high productivity. In December 2012, the mine took delivery of the first Sandvik MR340 roadheader that was locally assembled in China by Zhong Rui Mining Equipment Manufacturing Co. Ltd., a Sandvik joint venture. In January 2013 it commenced cutting roadway, and by early August it had excavated 1,200 metres of new passage under challenging conditions.
“In March we set a single-month record cutting 216 metres of hard rock, and then in May we surpassed that by going to 233 metres,” says Tian Xiyong, Ezhuang’s roadway development manager. “We have reached the place that the original production plan had scheduled for June of next year. We are cutting rock nine months ahead of schedule with the MR340.”
The roadway assigned to the MR340 is a difficult passage that originally would have required inefficient and hazardous blasting, says Tian, who is impressed that the cutting performance has not declined after repeated periods of high output.
About the Sandvik joint venture in China
(Zhong Rui Mining Equipment Manufacturing Co. Ltd.)
Sandvik’s joint venture partner, Shandong Energy Machinery, designs and manufactures equipment for the Chinese underground coal mining market. It is a subsidiary of Xinwen Mining Group, one of China’s leading coal mining companies.
While the focus of the venture will be to supply roadheaders to Shandong Energy Machinery’s parent company, Xinwen Mining Group, the goal of the joint venture is to become the leading premium roadheader supplier to the Chinese coal mining market.
Managers from other mines have grown curious about Ezhuang’s success.
“A colleague of mine who is the top decision maker at another mine is coming to see the MR340 next week,” Tian says. “Of course, we are conscious of the need to operate the machine as if we were flying an airplane – no incidents are permissible. Personnel must absolutely follow recommended operating instructions from Sandvik.”
Safe operation is a top priority at Ezhuang. Off the corridor to the elevator shaft is a large room full of batteries and lights on racks. Each individual set is locked beside a photograph of a miner and his family.
Blasting increases the risk of setting off methane explosions. Tian believes more mines in China should consider acquiring roadheaders to reduce reliance on drill-and-blast mining.
Li Jinbo, production manager at the joint venture, has participated in the entire process of introducing the MR340. A mechanical engineer by training, Li led the creation of a modern factory whose production team is staffed by more than a dozen young engineers and technicians. After training for three months at the Sandvik manufacturing plant in Zeltweg, Austria, they qualified to assemble the MR340 from its component parts.
Ezhuang is mining at seven different levels. The elevator shaft, built before the era of large equipment, was too small for several of the roadheader’s components. Sandvik and the mine improvised by suspending those pieces beneath the elevator.
Constrained by the original dimensions, the roadway in the Ezhuang mine is narrow and low – 5.4 metres wide and 3.95 metres high. The Sandvik joint venture in Shandong is also producing a low-profile version of the MR340 for sale to mines that are working in smaller spaces, as China’s mining companies require both large and small machines.
Senior Area Manager Yang Shunqiang, who leads production underground, is enthusiastic about the rock-cutting capability of the MR340.
“This is a very tough piece of equipment that allows us to make steady progress without long interruptions,” he says. “If we have service needs, Sandvik is available around the clock, regardless of what shift it is.”
About Sandvik MR340 Roadheader
Weight: about 55 tonnes
Equipped with a 230kW cutter motor
Maximum dust suppression and ignition prevention due to high-pressure pick flushing system
Easy and rapid assembly and disassembly through modular design
Proportional load sensing hydraulic system for optimal energy utilization