This excerpt taken from the CNX 10-K filed Feb 17, 2009.
Our exploration and development activities may not be commercially successful.
The exploration for and production of gas involves numerous risks. The cost of drilling, completing and operating wells for coalbed methane or other gas is often uncertain, and a number of factors can delay or prevent drilling operations or production, including:
Our future drilling activities may not be successful, and our drilling success rates could decline. Unsuccessful drilling activities could result in higher costs without any corresponding revenues.