Greater levels of automation and increased use of intelligent drive systems are the way of the future, according to Harry Martin, DBT vice president account management, who spoke to ILN at MINExpo in Las Vegas, in October.
Having worked in coal mining all his life, Martin has been responsible for all DBT customer-related activities since 1991. Martin believes Australian longwalling is an environment where state of the art technology can be applied to the products to give the operators a competitive edge. These include high seam shields; automation; very heavy duty shields; high capacity conveyors requiring special chains; and intelligent drive systems.
"The biggest conveyor we have operating in the world is in Germany but the same technology, the CST drive, applies where we can start the motors totally under no load, gradually apply the load and run the conveyor up to full speed without damaging the chain or the sprockets," Martin said.
Where the CST drive has major advantages over comparable drives is the ability to measure the load electronically. This means that in a situation such as a chain block near the headgate drive, the CST drive has the ability to immediately unload and disengage the chain. This is helped by the clutching mechanism being on the high-torque, low-speed side of the gearbox.
Where the CST drives come into their own, according to Martin, is with high capacity coal faces where load on conveyors can exceed 5000 tonnes per hour.
"It is difficult to imagine operating a conveyor at that capacity with reliability without a CST. Because it's so kind to the system it eliminates the shock loads and extends the life of the chain and sprockets."
Martin said a trend was developing, particularly in the United States, towards mining thinner seams. Martin said the only fully automated mine in the US was the US Steel Mining Company's No 50 mine in West Virginia. When the mine bought its plow system in 1989 it was the first fully automated longwall of its kind. Last year the mine upgraded to a state-of-the-art Gleithobel plow system and AFC, which began operations in March 2000. The seam thickness averages 1.25m and face is 320m long.
Technical features include Gleithobel plow guide 9-38 ve; plow guide welded to AFC, plow chain 38x137mm; plow speeds 1.98m/s to the tail and 0.99m/s to the head, installed power of 2x200/400kW.
Martin said in a hostile environment like a coal mine it made sense to introduce greater levels of automation to remove operators to a safer environment. The trend to greater automation will lead to more use of sensors, applying the information from sensors and taking corrective action, he said.
