The ergonomics of coalface machine operators in thin seams. (Leamon T, ed)

When the seam height is below 1 metre the problems of longwall machine mining increase. The work method of power loader operators is governed by the environment and face machinery. As the capacity of this equipment is increasing, there is littlereason to think that the work of the machine operator is likely to be lightened in the near future. An examination was made of the work of machine operators e.t three separate installations. The machine operator’s task, the power loader machine, the operators workspace, the noise, the lighting, the climate and the face performance were examined.Conclusions and recommendations are drawn from these studies which have general relevance to thin seam power loader mining.The outputs of the three installations studied were not limited by the performance of the power loader or the operator. However in the case of a Bi – Di shearer installation the machine speed varied with the operator by a factor of 10% although the operators showed no significant differences between the total output and the length of delays which they encountered. It is thought that this was due to the fact that the machine delays played a much rcore important part in determining output than the machine speed.These results indicate that the factor of overwhelming importance is the length of delay times. A description of these delays and what measures may be taken is given. Once these are reduced the indication is that the next bottleneck will be the speed of the machine arid more attention will be needed in the design of the machine and the support system.Studies of the operation of the machine show that the optimum control position for power loaders is at the front of the machine for each direction of travel. The present machines do not have their controls arranged in these positions neither do individual controls conform to ergonomic standards. It is possible to introduce immediate measures to reduce the risk of accidents due to some of these poorly designed and placed controls.Attention is drawn to the inadequacy of training both for the trainee and the instructor. Suggestions are made for the practical instruction of trainees and the development of their skill.The operators spent 12 – 20% of their shifts travelling to and from the face. The physical work level doing this travelling on occasions exceeded the level in operating the machine. Where long distances, gradients or low height conditions are involved it is adx’an tageous to install man-riding systems.The study of the operator in relation to the workspace showed that the operator was forced to crawl on his hands and knees in order to control the machines. The angular construction and size of floor cross members, the position of hoses, coal and stone in the travelling track aggravated the difficulty of crawling. It is advised that priority be given to devising a system to transport the operator in a prone position along the travelling track. The chief source of noise was the power loader. When cutting and loading the noise levels recorded were in the order of 93-98 dB(A). The operators exposure to noise during a shift depended upon the machine operating time. It is proposed that long terra research should be undertaken to reduce the level of the noise of machines where exposure is unduly high. Measures are proposed which can be implemented immediately.The lighting, while sufficient to prevent nystagmus, was not satisfactory for the operators steering task. Recommendations are made to ameliorate this condition.