The clinker was pulverized in rotary mills, crushed by steel balls. Both the factory and its environs were affected by the dust of crushed stone and coal, by the dust of cement and by the smoke coming out of the chimneys of the furnaces and boilers of the steam engine. The walls of the factory were encrusted with cement, which fell to dust and would harden later. Due to its heat capacity, coal is an essential element for obtaining the final product, clinker. The preparation of the coal to be used in the rotary kilns required a process of its own. The coal was transported by means of an inclined plane with funicular system to the warehouse. From there it went to a cylinder mill, where it was crushed, and passed to a rotary dryer cylinder located inside an oven, where the moisture was extracted. Then, to obtain powder, it was passed to a ball mill for refining; finally, the powdered coal was transported to the injector tanks of the rotary kilns.