Coal mine development roadway mainly shotcrete Support as a permanent support, and now support bolt tension test method for the specific operation as follows Anchor Mesh specific requirements. First, the construction technology and quality standards of the anchor bolt (1) Anchoring eye 1. Before

The roof is in short, that is, the air duct collapses. According to the extent of the roof's vertical fall and the severity of the casualties, common roof accidents can be divided into two categories: local roofing and large roof accidents. Omen of local roofing and preventive measures The occ

On April 10, the National Association of Sportsmen announced the production and sales data of China's passenger car market in March. According to the data, in March this year, the national narrow passenger car production was 2.156 million, a slight increase of 1.5% year-on-year, and the sales

1 External environment analysis (1) security issues into safe production of coal mine is an eternal theme, but must ensure safety in production inputs, lack of investment is difficult to ensure safety in production, planned economy period, the state-owned key coal mine safety technical measures fun

1. Anti-fire grouting technology Grouting can not only reduce the oxygen supply in the goaf, but also reduce the temperature in the goaf for fire prevention. It can also be used for fire prevention in a wide range of fire zones. 1) Soil to soil ratio The water-soil ratio is between 2:1 and 4:1, d

In the process of the development of new energy vehicles, there has been doubts about its environmental protection: "How many lands do the batteries of new energy vehicles have to pollute?" Indeed, as the number of pure electric vehicles keeps rising, there will be a large number of powe

GB 13456--92 Replace GB 4911--85 wastewater part and GB 8978--88 steel industry portion (Approved by the National Environmental Protection Agency on May 18, 1992, implemented on July 1, 1992) To implement the "Environmental Protection Law of People's Republic of China", "Wate