Table of Contents
- 1 What were the environmental impacts of room-and-pillar mining?
- 2 What gas is most likely found above a pillar fall?
- 3 What is it called when the roof of the mine is allowed to collapse?
- 4 What is the formula of strength of pillar?
- 5 Why is methane called firedamp?
- 6 How can we reduce the impact of mining on the environment?
What were the environmental impacts of room-and-pillar mining?
Underground mining for coal by longwall or room-and-pillar mining methods often interrupts and depletes groundwater and can alter its quality. Surface mining can enhance the introduction of surface water with dissolved solids into shallow and then deeper groundwater systems through fractures or other conduits.
Why uncontrolled failure of pillars in room-and-pillar method of mining must be avoided?
Once one pillar fails, the weight on the adjacent pillars increases, and the result is a chain reaction of pillar failures. Once started, such chain reactions can be extremely difficult to stop, even if they spread slowly. To prevent this from happening, the mine is divided up into areas or panels.
What gas is most likely found above a pillar fall?
| All references to the flame safety lamp below have been struck since these are no longer used in underground mines in the United States. | |
|---|---|
| A: | Methane. |
| Q: | What dangerous gas is most likely to be encountered above a pillar fall? |
| A: | Methane. |
| Q: | Why will Methane accumulate in an inadequately ventilated place? |
Why is room-and-pillar mining bad?
In room-and-pillar mines, columns of coal are left to support the ground above during the initial mining process, then they are often taken out and the mine is left to collapse, which is known as subsidence. It is these effects of mining that nobody sees but are the most troubling of all.
What is it called when the roof of the mine is allowed to collapse?
Retreat mining is the removal of pillars in the underground mining technique known as room and pillar mining. As the pillars are removed, the mine collapses because nothing remains to support the roof and overburden.
What is stope and pillar mining?
stoping, in mining engineering, the opening of large underground rooms, or stopes, by the excavation of ore. A common open-stoping method is room-and-pillar mining, in which pillars of ore are left standing to support the rock over a flat-lying ore body.
What is the formula of strength of pillar?
A common power equation is used for calculating pillar strength Sp, which can be expressed as a function of width-to-height ratio of a pillar and a constant:(7) S p = k · w α · h β where w is pillar width; h the pillar height; α and β constants; and k a constant representing the strength of coal material.
Where is coal formed?
The formation of coal begins in areas of swampy wetlands where groundwater is near or slightly above the topsoil. Because of this, the flora present produces organic matter quickly – faster in fact than it can be decomposed. In these areas, layers of organic matter are accumulated and then buried.
Why is methane called firedamp?
Firedamp is flammable gas found in coal mines. It is the name given to a number of flammable gases, especially coalbed methane. The gas accumulates in pockets in the coal and adjacent strata and when they are penetrated the release can trigger explosions.
Why is mine water acidic?
If you excavate coal, metal ores or other minerals, you may expose rocks and minerals that contain sulphur. If sulphur mixes with water and oxygen it can cause groundwater to become acidic. This is called acid mine drainage (AMD).
How can we reduce the impact of mining on the environment?
How can mining become more environmentally sustainable?
- Reduce inputs. The mining industry uses a large amount of water and land in their operations.
- Reduce outputs.
- Proper waste disposal.
- Improving the manufacturing process.
- Close and reclaim shut-down mines.
- Replenishing the environment.
- Final words.
What replaced room and pillar mining?
The oldest of the basic underground methods, room-and-pillar mining grew naturally out of the need to recover more coal as mining operations became deeper and more expensive. During the late 1940s, conventional techniques began to be replaced by single machines, known as continuous… …