One of the changes that occurs early in the book is the shift of the coal preparation from Coalwood to the newer mine in Caretta. This led to the tipple going mostly unused in Coalwood as all the coal was brought out and loaded onto trains in Caretta instead of in Coalwood. This also decreased the amount of coal dust in the air in Coalwood and significantly decreased the number of trains coming through town to pick up and carry away coal.
Some of the other big changes were the switches from men actually shoveling coal to using continuous mining machines, the ones that generated all the constant dust, etc. Of course this also led to the men getting black lung and other respiratory problems more frequently.