As the men took up arms and engaged in battle, in 1863 sonic mining was done to provide roof replacement materials for military purposes. The quarries nevertheless remained at a standstill for fifteen years after the war, reopening around 1880. They then produced their greatest yield during the following decade, with 5.000 squares of roofing slate, enough to cover 420 houses valued at $22,500, being produced in 1894. According to the U. S. Geological Survey, Georgia produced 38,097 squares of roofing slate from 1879 until the beginning of World War I, valued at 5165,918, although these figures are thought to be incomplete. It is reported that the total roof slate production of the Rockmart district was over 50.000 squares, enough to cover about 4,200 average size homes.
Rooting slate production dropped off after 1900 and was replaced by the quarrying of slate to make light-weight aggregate. The aggregate, known as “Gallic” was made by heating crushed slate to 2.000 degrees E. which causes it to expand.
