The agency said last week that the incident, which occurred at an unnamed operation, involved a Caterpillar/Bucyrus 30M3L remote controlled continuous miner with a Forced Potato model LOKN remote.

“During the accident investigation, it was determined that the second remote controller kept on the working section on charge for this continuous miner was used to move the continuous miner immediately after the accident,” MSHA investigators said.

“However, it was determined that by having both controllers available on the section and set to the same frequency, a situation could exist with the possibility that either remote controller could take control of the same continuous miner when in the range of the receiver.

This could become a danger and could lead to an unforeseen accident if a second controller was used without knowledge of the operator.”

The issue at hand is that the CM can continue to recognize the remote controller with the higher battery voltage and, even though just one remote should be used in the area at any one time with the other remote on charged or powered off, the potential still exists for both units to be active simultaneously.

Caterpillar has developed a controller/receiver program to detect other remotes in the vicinity by reading each remote’s unique transmitter ID code. If more than one remote transmitter is powered on and transmitting, the CM’s receiver can respond by automatically de-energizing the vehicle’s onboard pump circuit.

Also, Forced Potato will use remote serial numbers as unique transmitter ID codes sent to the continuous miner’s receiver.

MSHA has recommended that mines using Caterpillar/Bucyrus remote controlled continuous miners contact the OEM regarding the upgrade.