November 18, 2022 |
The absence of coal can be felt, not only in Hanna, but underneath the town, as well. The empty spaces left behind when the coal was removed as far as a century ago are causing problems today.
Carbon County was founded on coal. It was responsible for the founding of Hanna. Coal mining brought an influx of people into the area. When the coal mines closed, the town was left with miles of empty tunnels under it. The old mines are slowly collapsing, threatening to take anything on the surface down with them.
Many towns in the state are built on top of old mine tunnels. Seeing how the collapse of these workings can put entire towns in danger, Wyoming established the Abandoned Mine Land program in 1983.
Dave Pendleton, the Abandoned Mine Land program manager, said the first Carbon County settlements were formed specifically to supply the railroads with fuel.
Pictured above: File photo of Hanna town limits sign. Photo by Cali O’Hare/Bigfoot 99.
The Town of Carbon was the first community in Carbon County to provide coal for the railroad’s steam engines. When the coal ran out, Hanna was founded to take its place. Starting in 1901, coal mining was an integral part of the town. When coal mining stopped, the tunnels were left. Pendleton describes how extensive some of the workings are.
Using a technique called “room and pillar,” miners would hollow out an underground cavity, leaving sections to support the roof. Pendleton said they would manually dig out a space about seven feet high. Powered digging equipment would then be brought in, raising the ceiling to 25 or 30 feet, to extract as much coal as possible.
A century later, water and natural erosion have caused the mines to collapse. Voids under the Hanna Elementary School and football field have caused depressions on the surface, called subsidence. The problem was so bad that the Abandoned Mine Land division stepped in. The AML drilled holes from the surface into the mine and pumped 7,200 cubic yards of a special grout mixture into the void.
Pendleton said the space under the school was so large they were able to see water coming up from bore holes on the other side of the building.
The AML program manager said the grout will harden and make the ground no longer prone to subsidence. The Abandoned Mine Land division isn’t done in Hanna, however. Pendleton said shallow mines under County Road 297 have begun to show signs of collapse.
Abandoned mines are extremely dangerous. Supports preventing cave-ins can be a century old. Pendelton said one wrong move can be tragic.
The AML uses old mining and USGA maps, as well as satellite photography, to locate abandoned mines. They’ve started using lidar and computer learning to find mines hidden under trees or, otherwise, difficult to spot. If someone finds an abandoned mine, Pendleton said to call his organization.
With over 4,000 deserted and forgotten mines in the state, the Abandoned Mine Land division has their hands full. They’ve prevented further damage to the Hanna Elementary School and will continue to monitor the town for future mine-related issues.
