Time Required for Crack Formation

The time required for crack formation in material at 20ÉC (68ÉF) is about 10-20 hours. The lower the temperature the longer crack formation takes. The crack width for rock continues to increase with time and can become 10-30 mm (3/8" - 1 1/8 ") after several days, depending on free surfaces available. It is best to wait until the BRISTAR has worked to full depth before removing rock as premature removal at the first sign of a crack can hamper the leverage effect of BRISTAR.