NIOSH Mining Training Exercise


Bulls Double Header: Too Much Unsupported Roof

August 1994

See also: NIOSH mining products
Type: Paper and Pencil Exercise
Audience: Underground coal
Length: 29 questions
Skills Reviewed: Recognizing unsafe mining practices, Assessing changes in roof stability, Recognizing safe ways to clean up or re-support roof falls

You work at a mine that has approval to make 34 ft cuts using a remote controlled continuous miner. The roof bolting machine has broken down. The continuous miner has just been refitted with a new cutting head and bits that cut the coal much faster. The two roof bolter operators have been having a hard time keeping up with Bull, the continuous miner operator. At the face of #4 entry, Bull makes a 40 ft extended cut, trams back from the face, and then turns the miner and cuts the left-hand crosscut all the way through to the #3 entry. When the roof bolter operators discover Bull's "double header", they get the section foreman, and then try to plan a safe way to bolt this large area of unsupported roof. Shortly after they complete their assessment and plan of attack, a large roof fall occurs. Now the face crew must decide how to safely clean up the fall while advancing roof support.

Materials needed:
Instructor Copy
Problem Booklet 1 for each trainee. May be downloaded separately or duplicated from the Instructor's Copy.
Answer Sheet 1 for each trainee. May be downloaded separately or duplicated from the Instructor's Copy.
Optional Overhead projector and overheads of the Master Answer Sheet and Scoring Key found in the Instructor's Copy.
Page last updated: September 17, 2009
Page last reviewed: March 30, 2009
Content Source: National Institute for Occupational Safety and Health (NIOSH) Mining Division