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, 2008
Page last reviewed: May 30, 2008
Content Source: National Institute for Occupational Safety and Health (NIOSH) Mining Division