On part 36 diesel-powered permissible equipment, the engine’s exhaust gas is cooled before it exits the tailpipe.  Most machines use a water bath scrubber to cool the exhaust.  The exhaust gas is bubbled through water in the scrubber.  The hot exhaust gas evaporates the water in the scrubber that then has to be replenished.  Some systems require the water to be manually replenished while others have a water make-up tank that can automatically supply additional water stored on the machine.

One of these automatic make-up systems used on certain machines manufactured by Atlas Copco Wagner, Inc. (see attached list) had an overflow hole built into the scrubber.  This hole allowed excess water to drain from the scrubber.  The hole was incorporated into this design since excess water in the scrubber could, under certain conditions, flow into the engine through the exhaust pipe and damage the engine.  The scrubber was approved with this hole long before the DPM regulations became effective.

It has now been found that the hole permits the discharge of unfiltered exhaust gas.  This condition does not meet the DPM regulations and must be corrected.  Since the scrubber is part of the approved safety system, do not make any changes without MSHA approval.

MSHA is working with Wagner to redesign the system so that no unfiltered exhaust gas is discharged.  Owners of the affected machines will be notified by Wagner and MSHA when an MSHA approved retrofit is available.  MSHA's compliance assistance personnel will then work with mine operators to ensure the retrofits are installed in a timely manner. 

Mine Operators are requested to notify MSHA if they have one of the affected machines

at: 

                                    MSHA

Approval and Certification Center

Attention:  Mike Snyder

251 Industrial Park Rd.

Triadelphia, WV 26059

Tele:  304-547-2047

Fax: 304-547-2071

e-mail: Snyder.Michael@dol.gov