Dynamic model of a longwall shearer with a chain haulage system

Despite the pro-ecological policy, hard coal still is and for a long time will remain a valuable major source of energy in the world. It is usually found in the form of seams in underground mines. For many years, thin coal seams have been exploited on an increasingly large scale, therefore mines and machine manufacturers are looking for new, effective and safe methods of extraction. One of such methods is the use of a longwall system with a single-head shearer. This solution has been briefly described in the article, with special focus placed on the proprietary dynamic model of a longwall shearer with a chain haulage system. The model concerns a chain-hauled single-head shearer, but can be used to simulate coal ploughs, and to a certain extent, scraper and belt conveyors. There are models in the literature in which the chain is replaced by point masses. In the discussed model, the chain segments have been described as a continuously distributed mass, the value of which changes as the shearer travels along the wall. The shearer has been modelled as a rigid body with six degrees of freedom, placed on elastic skids. The load from cutting, loading and movement resistance has been taken into account in the model. The mathematical model has been saved in the form of scripts in Matlab. The set of scripts allows obtaining information about the behaviour of the shearer and the load on important structural nodes such as skids, chain and loaders fasteners or the driving shaft of the cutting head. The results also enable determining the power demand of the motors as well as calculating the required initial tension of the chain. The fully parametric model makes it possible to analyse the influence of a change in the values of significant parameters of the longwall working, drive units and shearer. This information is crucial at the stage of design construction and verification, which allows avoiding many errors in the prototype.