Effects of hydraulic stimulation on coalbeds and associated strata. Report of investigations

I n s tud ie s conducted by the Bureau of Mines, two t e s t a r eas were hydraul i c a l l y s t imula ted and exposed by mining: One i n the P i t t sbu rgh coalbed a t t he Vesta No. 5 mine, Washington County, P a . ; and one i n the I l l i n o i s No. 6 coalbed a t t he Inland mine, J e f f e r s o n County, I l l . Induced f r a c t u r e s were contained t o t a l l y wi th in t h e coalbed with no adverse e f f e c t on the s t a b i l i t y of a s soc ia t ed rock s t r a t a . Induced f r a c t u r e s were v e r t i c a l and were propagated normal t o the d i r e c t i o n of l e a s t r e s i d u a l t ec ton ic s t r e s s . Gas product i o n was increased f ive fo ld t o twentyfold by hydraul ic s t imu la t ion .