Human Induced Earthquakes: Section 3 | Underground Mineral Extraction


Anthropogenic Earthquake Week at CatMap

Mining Geologists Confirm That At Least Two Major Earthquakes Have Been Triggered By Mining


Similar in cause and effect to mega-dams and hydroelectric projects, mining and mineral extraction has been causing earthquakes and landslides for centuries. Some of the seismic incidents are infamous in their regions, and yet few citizens elsewhere have ever heard of them. There are no mines in Wilmette, IL or Short Hills, NJ, but we suggest that if there was a mining disaster there, the entire world would know. Mountaintop removal mining (MTR), which simply blows off the upper portions of a mountain, removes the coal, and dumps the toxic remains into the valley below, began about 20 years ago. Prior to that, underground mining was undermining surrounding communities for centuries and continues to do so on larger and larger scales around the world as humans scramble for dwindling mineral riches. The reasons mining causes earthquakes are the same as those in our first two topics: the removal or addition of massive quantities of rock and water from underground.

Undermining civilization

The worst earthquake in Australian history was caused by coal mining in Newcastle, NSW. It was destructive and costly beyond its numerical magnitude. Although it registered only 5.7 on the Richter scale, this December 28, 1989 seismic event not far from Sydney killed thirteen, injured 160 and caused $3.5 billion in damage. (According to one study, the cost of the damage was greater than the value of the extracted coal.) The effects of that quake spread over 77,000 sq miles with property damage to 38,000 buildings in a zone covering 3,500 square miles.The quake was caused by 200 years of mining in the area, which required pumping out 150 tons of water for each ton of coal produced. The water pumping alone can just mess up everything, as witnessed by the previously mentioned 2011 event in Lorca, Spain (Section 1).

Ways of Creating Stress

Underground mining removes the rocks and other material that used to be underground and does not replace it. It pumps massive volumes of groundwater out of the rock formations leaving empty spaces and changed pressures. Hence the disruption of the earth.So well-known are mining induced earthquakes that geologists have classified them into several categories. Underground digging and blasting disrupts the natural stress state of the geologic structure: the manner in which the blasting and digging is done predicts which category the seismic event will fall into. For example, the outer walls of a mine tunnel support the weight of the rock above, but in between the walls is empty space. When a wall collapses or explodes, you have what is called a rock burst, which blasts the tunnel with debris under high pressure and enormous force. That can cause an earthquake, sometimes a good sized one.

Newcastle-new south-wales earthquake

The largest known rock burst/earthquake was the collapse of a potash mine in 1989, which destroyed the German town of Volkershaesen with a 5.7 magnitude quake. This was strictly a man-made event.

The Crandall Canyon Coal Mine collapse in Utah in 2007 was another type of mine collapse called a mountain bump. It sounds kind of cute, but it managed to crank out a 3.9 on the Richter scale and kill nine people, not bad for a man made event.

While many of the catastrophic events we are experiencing during the Beginning of the End Times are to some degree the results of natural cycles, it is fair to say that far fewer of the two hundred mining induced earthquakes over the past centuries would have happened in the absence of greedy little human hands pawing at the earth.

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