Cloud Peak Energy Inc. drew little interest when it put itself on the block in November, raising the prospect the U.S. coal miner could be sold in pieces now that it’s bankrupt.

The company’s advisers talked to 21 potential buyers at the end of last year, but received only one proposal, which was a nonstarter because of “significant execution risk,” Chief Financial Officer Heath Hill said in a filing after Cloud Peak filed for Chapter 11 last week.

“We think...