Undergound transformer stations, battery charging stations, substations, rectifiers, and water pumps shall be housed in noncombustible structures or areas or be equipped with what?
A suitable fire suppression system
100
How often must carbon monoxide sensors be calibrated?
At least every 30 days
100
How often must smoke sensors be tested?
At least every 30 days
100
All monitoring systems used to monitor intake air ventilating battery charging stations shall be done with sensors not affected by what?
Hydrogen
100
What are three devices that must be provided on underground belt conveyors?
1. slippage switches
2. sequence switches
3. star/stop controls at intervals not to exceed 1000 feet
200
Lightning arresters shall be provided on telephone wires at what location?
Where the wires enter the mine and at the boxes on the surface
200
Where shall insulating mats be placed in undergound mines?
In front of disconnecting devices and all electrical installations where required
200
What are two conditions that ground wires must be tested for on a weekly basis?
Open circuit and high resistance
200
When shall power circuits in tipples, building, cleaning plants, etc. and all underground electrical circuits deenergized?
When not in use over a long period.
200
All undergound power ciruicts and electrical equipment shall be deenergized before work is done on the circuits and equipment except when ________ for trouble shooting or testing.
Necessary
300
When electrical work or major mechanical work is performed, a suitable disconnect providing visible evidence that the power is disconnected shall be locked open and a tag shall be posted on whom?
The individuals performing the work
300
Repairs or maintenance shall not be performed on machineary until the power is off and the machinery is blocked against motion, except where machinery motion is ___________ to make adjustments.
Necessary
300
What precaution must be taken when electrical circuits cross over or under belt conveyors?
The wiring shall be suitably protected
300
Switch boxers, contactors, controllers, and all other similar devices shall be kept free of significant accumulations of what?
Combustible dust
300
How high above the ground must high voltage lines be installed on the surface where there is a possibility of contact be traffic?
20 feet
400
What device shall be installed on all underground exposed power conductors and telephone wires entering a mine reguardless of voltage?
What other devices shall also be provided?
Lightning arresters
Also provided should be overload protection and disconnect switches of sizes and ratings approved by the department
400
Every metallic building in which electricity is used or connected with any circuit shall be what?
Effectively grounded
400
All transformer tanks shall be what?
Effectively grounded
400
Surface transformer tanks shall be housed or fenced in when lower than how many feet above the earth?
If used, how high must the fence be?
15 feet
If used, minimum of six feet
400
The OMSL may authorize the operation of any activity regulated be the OMSL to be conducted in a different manner than specified by law in under what conditions?
When scientific or engineering information is made available to the OMSL substantially indicating that the different manner would afford equal or greater protection and safety.
500
All electrical equipment except intrinsically safe equipment which is taken into or used inby the last open crosscut and in return airways shall be?
Permissible
500
Who shall reject any modifications to mining equipment which would endanger the health or safety of employees?
Comissioner or his authorized representative
500
Headlights shall be installed and maintained in a workmanlike manner and working order on what types of equipment at all times the equipment is in operation?
Mobile and face equipment
500
Headlights shall be mounted to provide what type of illumination?
Maximum illumination where it will be most effective