Abstract :
Carl Lee: There are a few examples cited in this paper which might require amplification or qualification for an engineer not familiar with this particular industry. Estimates are made showing returns of 6 to 20 per cent on the investment made on labor and fuel-saving equipment. Yet the cost in some cases runs up to nearly half a million dollars. The ordinary coal company would hardly decide to add so much to its capital investment for a small return. The normal conditions of coal mining are so frequently interrupted by strikes, poor market and competition that the smaller the mine investment the nearer the operator can come to breaking even in the long run.