Published in the August 2007 American Longwall Magazine
Joy Mining Machinery has offered a solution, it said, that can increase production and a flexible conveyor design that can help mines get the most from their continuous haulage system.
Joy's Matt Haaga discussed modern gateroad constraints and how the unit can help operations during an industry conference earlier this year.
Some of these obstacles are controllable, such as the degree of cross-cuts, the entry width and block, and the number of entries incorporated by the mine.
However, some constrictions can be anticipated but not necessarily controlled: floor and roof conditions, seam height and entry width are the key factors.
Mines, he said, are also working to overcome other production-based issues, such as keeping pace with longwall equipment offerings and advance rates, efficient panel pacing and possible longwall stall, and infrastructure and consumables management with greater footage rates.
To keep development rates up, operations are employing such methods as using long blocks, setting up single place mining in an entry with in-place bolting, reducing the number of entries, keeping belt line on and entries to lessen a double-belt set-up however, those processes often require longer continuous haulage.
Enter the 4FCT, a one-operator, remote-controlled system that Haaga explained as "a special flexible belt conveyor married to a flexible crawler unit" that has the ability to haul output and tram behind a miner at the same time.
Because the system can haul coal while the CM is cutting, downtime waiting on haulage is eliminated, and that waiting period is given back to a crew as opportunity for improved face advancement.
Equipped with a 42-inch belt available up to 570ft, the 4FCT can take on 27 to 30 tons per minute of coal output, even peak output of 41 to 42tpm.
The unit is hands-off, so the operator can view all of his or her surroundings, machine diagnostics and the miner and cable.
The line is equipped with a variable speed capacity Optidrive, so less dust and noise is emitted from the 4FCT.
Haaga added that the system could possibly be longer and as designed includes fewer transfer points.
Some application factors should be taken into account when considering the use of a 4FCT.
The well-ventilated operation should have belt storage systems already in place, have a low bolting density for support of overburden, and have a bolting plan and infrastructure in place that would support an uplift in production from an FCT system.
