When work started on the new RS20s, Joy anticipated it would require three years of development work to adapt the latest electronics available to the RS20s shields, but it turned into a five-year endeavour.

“The progress in electronics themselves was so rapid it was sometimes difficult to keep our development exercise abreast of what was occurring,” Joy longwall sales coordinator Pete Crossland said.

While the RS20s applies largely the same software as the earlier version RS20 shields, Joy made significant changes to the hardware, the actual electronic interface—where the fingers meet the buttons—the electronic boards, cables, and the entire computerized system.

Advances in the electronics mean the new system is 50 times more powerful than that available previously. This has made video streaming possible, together with face communications, the Armoured Face Conveyor (AFC) lockout controls, and the lighting system. In essence, Joy has created a system capable of integrating all of these . What comes next is dependent on just what the customer wants the system to do.

“With RS20s, Joy has taken a leap ahead of the pack, setting the agenda that Joy’s future market is not in the low spec, low life market, but, rather, in the high scale technological end. In Australia and the US, and now more in Russia, China, and India, they recognize the cost of quality, and appreciate that quality does cost. Increasingly, they are willing to invest at Western prices for Western quality,” Crossland said.

Last year, a Russian mine set a local record of 4 million tonnes with an all-Joy longwall mining system. In China, a customer with two longwalls and Joy continuous miners produced 16.2Mt in one year, demonstrating how both countries are rapidly catching up with, and even overtaking, production in the West.

One solution to increased longwall output is going to wider longwall faces. While longwalls used to be limited to 200 supports, now, with the RS20s, there is no limit on the number of shields.

“When that happens, when that capability of super-extended walls is applied, the shearer will be spending more time cutting coal on the face and less cutting cycle time in the face ends, which means more coal per minute more consistently,” Crossland said.

This means, of course, the shields must keep pace with the shearer, placing big demands on fluid transfer through the hydraulic system, which led to the development of Hi-Flo Compak valves, first supplied in 2002.

Software and hardware improvements, and the hydraulic system itself, allows the RS20s to keep up with a shearer operating at 200 feet per minute, about 40fpm faster than today’s shearers are capable of flitting. As the faces get longer. the speed of the shearer and the quick cycling of the shields become more important.

Recently, Joy received an order for the first 400m face incorporating 2.05m supports and 2.05m pans, along with the new Joy BROADBAND Low Profile Chain.

At that length, a standard chain hunts up and down, or oscillates, which leads to major problems. The BROADBAND Low Profile Chain is designed for heavy duty and capable of larger loads without oscillation.

“On the stage loader, the chain and sprockets are in contact five to six times more often than they will be on the AFC,” Crossland explained. “We fully expect at least the same 200% increase in chain life on the AFC. Again, the aim being to match the life of the sprocket and chain to the panel reserve, say one of 10Mt or two reserves of 5Mt each,” Crossland said.

In tests completed in Australia, where the BROADBAND Low Profile Chain was installed on a stage loader, the new chain demonstrated very long wear.

“Testing the BROADBAND Low Profile Chain on a stage loader is very much like New York,” Crossland said. “If it can make it there, it can make it anywhere”.

With longwalls now capable of producing 5000-6000t per hour, the limiting factor for the longwall becomes outby transportation, particularly power, gear boxes and drives.

“On Joy’s extended walls, we apply three 1000kW motors with associated gear boxes and transmissions. With the capabilities the RS20s shields and the BROADBAND Low Profile Chain have given us, we are developing larger transmissions and looking at 1500kW drives.

“Today, there are 32 fully automated JOY longwall mining systems in operation worldwide, two-thirds to three-quarters of all the fully automated systems out there,” Crossland said. “All of them are using the same software on their RS20 shields as is employed on the new RS20s shields, making it possible for any or all of them to move up to the RS20s with minimum changes in operation.”

Crossland believes the trend is toward ever more automated systems in order to keep the operator out of the dust, as has been the case in Australia and the US. Another key issue for the OEM is availability, with Joy aiming for longwall availability in the high 90 percentile.