Show less coal used in making coke the quantity of coal required to produce a ton of coke Is much lesi than formerly the average gain in 1912 compared with ten years ago li probably at least pounds it li doubtful it in the earlier years the actual yield of coal in coke exceeded 60 per cent whereas in 1912 it was 67 per cent according to the united states geological survey abla gain Is largely due to the increase in the production ot by product coke in which the yield of coke a ton of coal very much higher than la making be hive coke |