Chalk (1940-1949)

British Instructional Films Ltd presents a Classroom Film. Chalk mine or quarry. Man makes a hole in the side of a chalk face. He inserts a stick of dynamite or explosive of some sort. The explosive is pushed further into the chalk. Explosion brings large area of chalk crashing down. A man smashes two large pieces of chalk together to show how it breaks up. Another man shows two pieces of flint to the camera and demonstrates how these do not split up when knocked together. Men at top of cliff face knock more chalk down. A mechanical digger is used to move large amounts of the chalk. Small train pulls crates of chalk to the refinery. The chalk is tipped into a wash-mill. Machinery moves the chalky water around. The mixture is passed through filters to storage tanks. It is then pumped to presses which squeeze out the water. Water pours out and into a trough. Slabs of chalk are then taken out of the press and placed on a barrow. The cakes of chalk are then taken to the drying rack. Wh