【正文】 ter systems,with pulses or data fed dowa the shearer trailing cable,to the roof support control ,unreliability and the need to interface to numerous types of shearers imposed enormous difficulties with this approach.Gullick decided that infra red was the path to take,and developed a system with the following main attributes: broad,powerful infra red beam capable of punching through dust. coded infra red transmission to ensure that the system was not activated by cap lamps or lumimaires.,which could tolerate,and be programmable to,the occasional lossofsignal.This system was a success and led to immediate customer benefits in terms of increased production and reduced manpower.Because the Gullick Electroflex system was microprocessor based throughout,it was easy to extend the flexibility of the system,both machine and maninitiated,to cater for the multitude of customer requests that followed,Customers who saw the successful potential of the early software programmes developed the system proactively,alongside the sofeware team of Gullick to provide the following facilities:1. Retries2. Anti relaybar pin breakage3. Face end sequences4. On face selection of out mode5. Dual machine sequence The Electroflex systems of today are versatile and initiation is often specified,and the most recent retrofit of such equipment at West Cliff,for example,has resulted in the face producing record tonnages under machine initiation control.The current system still uses the motorized valve and other basic philosophies going back directly to the 1984 system at Sherwood,and indirectly to the earliest microprocessor systems from the late 1970s.Motorised valves,along with the main flow valves,have been miniaturized and improved and form the Monobloc series of valvegear.Electronic equipment uses newer chips but still embodies the basic circuit building blocks and software built up throughout a track record of 15 years use of onface microprocessors.As well as control,monitoring of leg pressures can be provided and even face alignment is available(though not currently popular due to improvements in ram system efficiency),thereby fully pleting a circle first embarked upon in 1978.So the dreams and objectives of those engineers who first conceived ROLF in the late 1960s –automation,machine initiation,manless operationare achieved what of the future?6 ROOF SUPPORT AUTOMATION IN THE FUTUREThere are several developments which are currently poised to take roof support automation into a new generation where integration with other systems on the longwall will bee monplace.Roof support systems themselves will bee more automated,with software and hardware developing to make the systems more intelligent and thereby capable of dealing unaided with more marginal conditions and intrinsic mining problems such as roof ,for example,systems for controlling 4 leg supports,providing canopy balancing using tilt sensors to limit the penetration of the rear of the support into cavities,have been developed.Programming developments and new sensor technology will enable the roof support systems to continue to be enhanced to take care of themselves,and ‘expert’ system programming, where the system learns from its own mistakes, is on the horizon.However the roof support system is no longer the only ‘smart’ system on the longwall. Shearers,AFCs and switchgear control and environmental monitoring equipment all have builtin intelligence.As needs dictate, automation in the future will connect these various intelligent systems together in order that information can be transferred between the systems, to the benefit of all.Various coal operators throughout the world are now taking this local integration approach, and the mon objective is to improve reliability and productivity of the equipment, while permitting easier management of maintenance tasks.In the medium term it seems likely that the separate subsystems may themselves bee integrated and bee a single unit. Modern microprocessor and programming technology is already at the point where that is technically feasible and it is only a question of ‘how long’ and not’if’.When the integration process is developed to the full and each sub system of the face is programmed by an ‘expert’ system,there may finally be an opportunity to install the first fully manless face. Until that time it is difficult to see any major reductions in manning levels beyond what is achievable today with machine initiation and robotic shearers.7 CONCLUSIONThe path to roof support automation has been trodden and a successful oute finally arrived at.Many factors have contributed and it is indeed a credit to the many engineers,designers and users who have been involved in the subject that the dreams of 35 years ago have been achieved.As the coal industry steps forward into a new era of energy petitiveness,the role of automation will bee increasingly important as a primary means towards higher seems,at present,still to be a long path of opportunity ahead for roof support automation.