This book tells how mines evolved from simple bell pits into extensive networks of shafts & tunnels & extending deep underground. It describes the methods used to drive tunnels through the rock & the machines that were developed to cut the coal. It explains how the coal was transported from the coalface to the shaft, a task performed variously by women or children with sleds of baskets, pit ponies, rope haulage systems, conveyors & locomotives, & it describes the winding engines used to lower men & equipment into the mine & to bring them & the coal back to the surface.