Electricity in mines

The mining industry is one of the largest producers and users of electric power in this country. It is generally assumed that the methods of production and utilization are not as economical as they might be. The following notes of some efforts to achieve efficiency and increase reliability, together with results of tests made with this end in view, may be of general interest. For the purpose of reference the paper is divided into three parts:¿ Part 1 deals with the general problem of power production at mines, giving briefly the essential differences between a colliery power plant and a normal power plant. Part 2 deals with the modern methods of supplying the four main power-consuming units at mines, with particular reference in each case to the question of the utilization of synchronous motors, and also discusses the advantages and disadvantages of alternating-current and Ward-Leonard control for electric winders. Part 3 gives the results of progressive conversion of several mines from steam to electric drive for the various main units and also the effect of supplying compressed-air power from a central station in a similar way to electric power.