At the end of this module, you will be able to:
- Identify the common physical features of surface mines
- Define the angle of repose
- Describe why the angle of repose is critical to mine safety
- List several uses of berms at surface mines
The following key questions are answered in this module:
What are common physical characteristics at surface mines?
Surface mines typically include the pit, benches, highwalls, stockpiles, wastepiles, settling tanks or ponds, berms, and haul roads.
What is the pit?
The dominant feature in an open pit or quarry operation is the pit, a broad, deepened, often funnel-shaped area where overburden has been removed to access the material to be mined. This is where material extraction takes place.
What are benches?
Benches are terrace-like steps built into steep hillsides or into the sides of an open pit to prevent slides above active mining areas.
What are highwalls?
At surface mines, highwalls are unexcavated faces of exposed overburden which can range in height from 20 feet to well over 100 feet depending upon the geological characteristics of the mine and the material being mined.
What are stockpiles and wastepiles?
Stockpiles and wastepiles are volumes of mined material which have been built up by conveyors or haul truck dumping.
What are settling tanks or ponds?
In operations where aggregate and other potential construction material is mined, washing may be part of the process. The resulting wash water may be piped to settling tanks or ponds where it can be reused after unwanted sediments have settled to the bottom.
What are berms?
Berms are long, low piles of material built up to at least the mid-axle height of the largest mobile equipment which usually travels the roadway at the mine. They are placed and maintained in specific locations in order to clearly define safe limits of vehicle passage and dumping.
What are haul roads?
In addition to providing truck haulage paths, haul roads define the general operational flow of equipment and material throughout active mining areas.
Below is a transcript of the video sample provided for this module:
At surface mines, highwalls are unexcavated faces of exposed overburden, which can range in height from 20 feet to more than 100 feet, depending upon the geological characteristics of the area and the material being mined. The slope and condition of the face of the highwall may also vary significantly, depending upon the nature of the stone or sediment. For example, highwalls of consolidated stone may be vertical or nearly vertical, while those of unconsolidated material and sediments may retain the slope at which the material naturally comes to rest.
Use the additional resources and links below to learn more about this topic:
- US Department of Labor, Mine Safety and Health Administration (MSHA) – www.msha.gov
- MSHA Associations - http://arlweb.msha.gov/MINELINK/NATIONAL.HTM
- MSHA Library - http://arlweb.msha.gov/TRAINING/LIBRARY/mshaPortal/content/research_brief.html