New life for old bolter miners

Bolter miners used in underground coal mining have a tough life in the harsh conditions in which they operate.

After just four to five years of life underground, they can look almost worn out, but in the case of Sandvik's MB series of bolter miners, these machines have the inherent durability and strength that allows them to be completely rebuilt to as-new condition.

There are more than 50 of the MB series machines operating in mines in NSW and Queensland, making them the leading machines in underground coal mine longwall development applications, according to said, Sandvik's project manager of overhauls in mechanical cutting underground coal, Troy Robertson

"An important element of the economics of running bolter miners is their ability to be completely rebuilt from the ground up a number of times during their working lives," Robertson said.

"A key part of Sandvik's service and support offerings for our MB series machines is our capability of carrying out these rebuilds to original equipment manufacturer standards, and with full factory warranty."

Sandvik bolter miners are electrically powered, track-mounted continuous mining machines designed to excavate longwall development roadways and install roof bolts simultaneously in underground coal mines.

Their ability to carry out simultaneous cutting and bolt­ing greatly speeds up production, resulting in substantial economic and safety benefits.

Sandvik's MB series bolter miners are safer, uniquely efficient, high-capacity solutions for both rapid entry development in longwall mining and full-scale production in room-and-pillar mining.

The cutter drum is mounted on a hydraulically actuated sliding frame, giving it the ability to sump into the face independently of the mainframe and tracks. And since the roof and rib bolters are mounted on the stationary mainframe, they can be operated throughout the cutting cycle.

Manufactured by Sandvik in Austria, the original ABM series dates back to the early 1990s, and the range has undergone continuous upgrading and improvements since introduction.

"The main models we sell in Australia are our MB650 and MB670 bolter miners – these fit with the seam heights for most longwall mines looking for bolter miners in their operations," Robertson said.

"It's a market segment that's unique to Sandvik; as a result of our ongoing engineering design, performance, safety and ergonomics, no other supplier has been able to deliver the required combination of production, safety and ease of operation.

"The rule of thumb is that after three rebuilds, with four to six years between rebuilds, the technology in our MB series has developed to the extent that the price to upgrade to the latest specifications ceases to become economical.

"In addition, compliance requirements are ever-changing, and bolter miners have to comply with all the latest safety standards before they can go back underground."

Today, all MB series bolter miner rebuilds in Australia take place in Sandvik's Heatherbrae facility, north of Newcastle, NSW.

"We have a dedicated MB series rebuild facility at Heatherbrae, with the ability to take a tired bolter miner and restore it to as-new factory-warranted condition," Robertson said.

With capacity to carry out six full rebuilds a year, the great bulk of the rebuild work is done by trained Sandvik technicians, including the initial mechanical stripdown, engineering, electrical systems, gearboxes, components, bolting systems, and upgrades, followed by re-assembly, function testing, commissioning, painting and detailing.

Robertson said that Sandvik offered MB series machine owners the only option to ensure fully compliant, factory-certified rebuilds.

"In addition, the only way to access the latest technology upgrades is through our OEM upgrades, which are then backed by full six-month factory warranties," Robertson said.

"Before we start a bolter miner upgrade, we carry out a full engineering feasibility study, so the customer knows what is legally required, as well as what additional options are available – and the benefits that those options will bring.

"We do a lot of work up front to ensure our customers get the best end-product they possibly can out of our rebuilds, so they know exactly what they will get, with no surprises."

Robertson said that feedback from customers who have had rebuilds carried out, which includes the major mining houses, has been universally positive.

"Following every rebuild, we ask customers to fill out a feedback form on how well we have performed across a range of critical areas.

"The feedback we receive rates us very highly in the quality of our service and workmanship, the degree to which we keep customers informed of progress, developments and issues, our flexibility once rebuild work commences, and our ability to upgrade machines to incorporate latest technology and innovations," he said. 

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