Ground Control


Question Answer Notes
When next to a highwall, never park equipment _______ to it. Never put yourself ______ the highwall and equipment. parallel; between Always keep a safe distance from a highwall. Never park equipment parallel next to a highwall. Never put yourself between a highwall and a piece of equipment — have an escape route! Never enter an area that has not been inspected. Never enter an area until you are aware of all current and potential hazards.
Which does not describe a rock mass failure? A. Can involve a relatively large amount of material on a large portion of a highwall; B. Possible to predict; C. Impossible to predict C. Impossible to predict A rock mass failure can involve a relatively large amount of material on a large portion of a highwall. It is possible to predict rock mass failures with modern monitoring techniques and attention to warning signs.
Which is a seismic event that causes injury to persons or damage to underground workings due to its sudden, violent nature? A. Rock fall; B. Volcanic eruption; C. Rock burst C. Rock burst  
What is the control method used to remove unstable or possibly loose rocks using hand tools or equipment? Scaling  
To be most effective, rock bolts should be installed at what angle to the rock surface? A. 90 degrees; B. 45 degrees; C. Less than 10 degrees; D. It doesn’t matter A. 90 degrees  
True or false: You should never go under unsupported ground for any reason. True  
Ground conditions that create a _______ to persons must be mitigated before work or travel is permitted in the affected area. Hazard Underground: Never go past the last rock bolt. Surface: Never go into an area that has not been inspected to ensure ground stability.
In surface mining, debris at the toe, raveling, tension cracks, and overhangs may be indications of this unwanted ground condition.


In surface mining, this ground control involves removal of unsecure material from a face or highwall. Scaling  
Sudden appearance or accumulation of this may be an indication of potential ground instability. Water  
This potentially hazardous condition can cause instability when the ground expands and contracts due to extreme fluctuations in temperature.

Freeze and thaw

What term refers to the steepest angle at which a sloping surface formed of a particular loose material is stable? Angle of repose  
Catch berms and secondary supports for surface mines, and shotcrete and wire mesh for underground mines are all controlled installed to mitigate what hazard? Rockfalls  
Name one geological structure that may influence ground instability. Joints; steeply dipping beds; faults  
Persons must not work or travel between machinery or equipment and this type of structure when the machinery or equipment may hinder escape. Highwall  
Name an extremely common method of monitoring slopes in a surface mine. Prisms; inclinometer; GPS; drones; lasers; radar  
What is the most prevalent type of underground rock support to promote rock stability? Rock bolts  
What sound does loose rock make when scaling? A. A high-pitched “ting”; B. A low drumming or “thud”; C. It does not make a sound B. A low drumming or “thud”  
True or false: Water is detrimental to ground control. True  
What signs are associated with unstable ground? A. Cracks; B. Rubble at the toe; C. Exposed bolts; D. Changes in water flow; E. All of the above E. All of the above  
How do drill and blast procedures affect ground control? A. They create smaller rocks; B. They shift stresses in the rock from compression to tension; C. They create unsupported ground; D. All of the above C. They create unsupported ground  
Ground Control Safety typically considers which element for both surface and underground mines? A. Water and other influencing agents; B. The gravitational constant; C. Natural weathering through the freeze/thaw cycle; D. Stresses from rock overlying the drift A. Water and other influencing agents  
True or false: It is acceptable to travel under an unsupported roof if you are performing a heading inspection. False  
True or false: It is common to verify the quality/performance of installed ground control systems using visual inspection only. False  
Which two of the following indicate problems/issues related to ground control systems that are improperly installed or unsuitable for the environment? A. The improperly installed systems cannot be replaced; B. They give people a false sense of security; C. They may fail quickly and catastrophically; D. They save money for the mining operation B. They give people a false sense of security; C. They may fail quickly and catastrophically  
Which is a generally accepted rule of thumb for arbitrarily working in or visiting the impact zone of a highwall? A. That you must be escorted by the ground control engineer and the highwall has been inspected within the past 96 hours; B. That you remain as close the highwall as possible and no more than half the highwall height minus fifteen feet; C. That mine production must be ongoing in the immediate area; D. That it is is a bad idea D. That it is a bad idea  
When scaling to detect loose rock, what sound do you listen for? A. Dull thud; B. Sharp ring; C. Crashing of falling rock; D. No sounds A. Dull thud  
What signs can indicate unstable ground? A. Rubble at the toe of the highwall; B. Fault zones; C. Steeply dipping beds; D. Water; E. All of the above E. All of the above  
Which is not a type of underground rock support? A. Timber; B. Shotcrete; C. Rock bolts; D. Rubber pillars D. Rubber pillars  
True or false: You should never travel or work inby the last row of bolts. True  
Why do we want to prevent a fall of ground? A. To prevent injuries and fatalities; B. To avoid compromising mine ventilation or escapeways underground; C. To increase production with the fallen rock; D. A and B; E. A and C D. A and B  
True or false: Large blocks of rocks are typically more stable and easier to control than small blocks. True  
Name one visual sign of ground instability. Rubble at toe of highwall; closely spaced joints; fault zones; overhangs; cracks above highwall; steeply digging beds; loose or blasted rock on face  
What is one way to keep highwalls safe? A. Scaling; B. Spraying; C. Dusting; D. Covering A. Scaling  
Concerning ground control, what is the most important safety measure you can take? A. Never get out of your vehicle; B. Inspect the area regularly; C. Stay out of incident zones B. Inspect the area regularly