The National Coal Board (NCB) Film Unit is one of Britain's most substantial and long-lasting industrial film units. The following is an informative film describing what Strata is and how it needs to be controlled in a coal mine. Title - Strata Control Title - What are Strata Using illustrations, a narrator explains what Strata is (layers in the earth), and how in coal pits it is important to use roof beds to support the Strata. Title - Strata Control on the Face Footage from within...

The National Coal Board (NCB) Film Unit is one of Britain's most substantial and long-lasting industrial film units. The following is an informative film describing what Strata is and how it needs to be controlled in a coal mine. Title - Strata Control Title - What are Strata Using illustrations, a narrator explains what Strata is (layers in the earth), and how in coal pits it is important to use roof beds to support the Strata. Title - Strata Control on the Face Footage from within mines shows the flatbed machinery which is used, and how they move as the mining moves along. Photographs are also shown of wire mesh beds placed over the coal face, another method of supporting the Strata. Title - Strata Control in the Roadway The kind of support and control needed depends on the permanence of the underground road way. This is demonstrated through example of long underground roadways, and permanent pit railways. (The film is incomplete.)