Will coal mining cause soil erosion?

Coal mining can cause cracking of the mountain, collapse, landslides and subsidence, and increased hydraulic conductivity of the soil, the soil moisture and nutrients huge loss, reduced soil fertility, crops and trees pose a threat to growth. The destruction of water resources systems by coal mining is also very serious. Environmental protection is also important for mineral rights trading.
During the coal mining production process, the goaf range is continuously expanded, forming a peak of water in the whole mining process. The surface water is rapidly converted to groundwater, and the groundwater body is changed from the original lateral movement to the longitudinal movement, destroying the shallow water source. , seriously affected the industrial and agricultural water use. The surface runoff is significantly reduced, and the groundwater level is greatly reduced, resulting in a series of problems such as cracking of building buildings, water subsidence on the ground, sinking of river banks, reduced flood discharge capacity, and spring water cutoff.
Example: In 1994, the well-known Jinci Difficult Spring was shut down due to over-exploitation of coal. The pollution of surface water by coal mining mainly through two ways: mine drainage and leaching of vermiculite directly cause pollution to surface water flow. The pit water not only mixes a large amount of coal dust and harmful elements, but also is seriously polluted by underground rotted pit wood and oil. After being discharged from the surface, the river water flow is directly polluted. Gangue rich in soluble ions, in particular heavy metal ions, in the surface water and groundwater erosion, leaching, can easily migrate to the water pollution.

Low Noise Laser

The low noise issues of lasers are due to the competition of mode in Laser resonant cavity, which lead to high frequency jitter of output power. Through special design for laser resonant cavity and other components, the laser amplitude noise can be reduce efficiently. CNI low noise laser can be widely applied to DNA sequency, cell sorting, spectrum analysis, interference measurement, laser holography, photo processing and biomedical and other fields.

CNI offers low noise lasers in wavelengths from ultraviolet to infrared (360~1550 nm).

Features:

Beam spot pattern: TEM00

MÂ²: <1.1

Pointing stability: <5Î¼rad/â„ƒ

Constant temperature (23Â±3â„ƒ) noise: -52dB

Noise stability (RMS@4h): <0.2%

Bandwidth: 20Hz~20MHz