Mining accidents occur in the process of mining metals or minerals. Thousands of miners die from mining accidents each year, especially in the process of coal mining and hard rock mining. Generally speaking, surface mining usually is less hazardous than underground mining.
Most of the deaths today occur in developing countries, especially China. China's coal mines are the world's deadliest, killing an average of 13 miners a day. China accounts for the largest number of coal-mining fatalities, about 80% of the world’s total, although it produced only 35% of the world’s coal.
As a comparison, annual coal mining deaths numbered more than 1,000 a year in the early part of the 20th century in the U.S. They decreased to an average of about 450 annual fatalities in the 1950s and to 141 in the 1970s. The yearly average in coal mining decreased to 30 fatalities from 2001-2005, though 60 to 70 miners still die each year in the U.S. coal and non-coal mining industry. The most common accidents occurring in the mining industry are the result of poisonous or explosive gases or mishaps relating to the use of explosives for blasting operations.
Methane and Consecutive Coal Dust Explosions
Methane is a highly explosive gas trapped within coal layers. Mechanical errors from improperly used or malfunctioning mining tools (such as safety lamps or electrical equipment) or the use of improper explosives underground can trigger methane and initiate consecutive coal dust explosions.
Methane and coal dust explosions have caused the largest mining disasters in history and frequently kill or trap underground miners. The tragic Courrières accident, the worst ever mine disaster in Europe, was directly caused by methane and dust. It caused the death of 1,099 miners in Northern France on March 10, 1906.
The Courrières accident is said to be the second deadliest mining disaster; the largest one remains the Benxihu Colliery accident in China which killed 1,549 miners on April 26, 1942.
Blasting Related Accidents
Blasting consists of using explosives for rock breaking purpose. Proper, and (even worst, obviously) improper, use of explosives could lead to dangerous situations such as:
Fly-Rocks: "For the past two decades, most explosives-related injuries and fatalities in surface mines occurred when workers were struck by rock, either because they were too close to the blast or rock was thrown much farther than expected. In underground mines, most explosive-related fatalities were caused by miners being too close to the blast, followed by explosive fumes poisoning, misfires, and premature blasts," according to the National Institute for Occupational Safety and Health (NIOSH)
Premature Blast: "The detonation of an explosive charge earlier than warranted. A premature explosion may be due to carelessness, accidental percussion, a faulty fuse, or degenerated explosives," according to the Dictionary of Mining, Mineral, and Related Terms.
Misfires: "Misfire means the complete or partial failure of a blasting charge to explode as planned." (Definitions for Surface and Underground Metal and Nonmetal Mines, Department of Labor, Mine Safety and Health Administration (MSHA),30 CFR Parts 56 and 57, Sec. 56.2, Volume 69, Number 124, pages 38837-38843.
The explosive or pyrotechnical products that remain in the ground or in the 'muckpile' might be triggered by any mechanical effect during the digging, milling or crushing stages of the mining process, causing injuries or fatalities to blasters or operators.
Mine-Induced Seismicity: Especially dangerous in underground mining areas, mine-induced seismicity also causes slope instability in surface mining, and is a major threat for all miners.
Mines located in seismically active regions, such as the Andean region (also known to be one of the wealthiest metallic mining zones in the world), are even more at risk. The use of explosives might cause earthquake-like events that collapse mine workings, and traps miners in, as happened to the 33 miners stuck underground from August to October 2010 in a Chilean mine near the city of Copiapo, or kill them, flood the mine and damage structures on the surface.