See also: NIOSH mining products
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| Type: | |
Invisible Ink Exercise |
| Audience: | |
Surface mine electricians |
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Length: | |
5 questions |
| Skills Reviewed: | |
Electrical troubleshooting, Safe work practices |
The surface mine where you work receives its power from a 138 KV utility line that is stepped down to 25 KV for pit distribution. Substations make further reductions to 4,160 volts for operation of smaller equipment such as drills. The pit electrical distribution system has worked well. Then a problem develops. Power leaving a portable substation goes through two boxes to a drill. A ground fault occurred in the system and tripped box A. The flag was reset and the system held for about a week. Then the ground monitor trips box B. Within a few days box A trips two more times. As a mine electrician you must find and correct the electrical problem so that production and safety can be maintained.
| Materials needed: | |
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Instructor Copy
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Problem Booklet
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1 for each trainee. May be downloaded separately or duplicated from the Instructor´s Copy. | |
Answer Sheet |
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1 for each group of 3 or 4 working the exercise. Purchased from MSHA (http://www.msha.gov/Education&Training.htm, MSHAdistributioncenter@dol.gov). You may also duplicate them locally if you or a local print shop have the ability to print invisible ink. | |
PENIB Developing Pens |
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1 for each answer sheet. Order from SICPA, Customer Service, 8000 Research Way, Springfield, VA 22153, Phone 1-888-SICPAUS or 1-888-742-7287, pen # "PENIB", a broad tipped developing pen. | |
Optional |
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Overhead projector and overheads of the Master Answer Sheet and Scoring Key found in the Instructor's Copy. | |
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