Lafayette’s underground avenues

Broadway, the underground haulageway for the Simpson Mine in Lafayette, Colo., ran north-south as shown on this progress map. This area of underground passageways was about 240 feet below the surface in about the 400 block of East Elm Street.

Lafayette’s dirt streets circa 1910 didn’t see a lot of traffic. Although trains ran daily between Lafayette and Denver, local travel was primarily via horse and buggy, and only a handful of households could afford a Ford Model T. Residents getting around on bicycles had an ally in the Arc Light Bicycle Shop in 400 block of East Simpson, and horse hitching posts fronted almost every commercial establishment.

Two hundred feet under Old Town Lafayette was a different story.

The Simpson Mine, opened in 1889 and sited squarely under Lafayette’s minimal town limits, was at peak production, cranking out dozens of train car loads of coal per day. Almost 400 men and three dozen mules toiled in the mine’s oil lamp-lit passageways, blasting, loading and hauling one-ton coal cars to the main shaft for lifting to the surface.

All of the coal collected from the far boundaries of the Simpson Mine — coal mines generally tunneled to the far reaches of their mineral interest, then worked backwards toward the main shaft — made its way to the lift via 60-foot-wide passageways, called haulageways. These underground avenues radiated a half mile on each side of main shaft in the 700 block of E. Cleveland Street.

And they were very busy avenues.

The haulageway that miners named “Broadway” went north from Simpson Street. The Wabash haulageway went south from Simpson Street, the Long Branch followed Public Road, and the Timber Line went west along West Simpson Street.

A haulageway had parallel 10-foot-wide tunnels, separated by 40 feet of coal. Crosscuts connected the two tunnels every 20 to 30 feet. Tracks dedicated to hauling the coal-laden carts often had what local miners called “pardons,” which was the equivalent of a train switching yard (only underground). Coal cars were pulled by a single mule and navigated by a mule driver. Permanent timber bracing was often used to support the tens of thousands of tons of rock overhead in the haulageway, and large stands of cool, called pillars, were left in place on each side of the haulageway.

Most other mine passageways, called entries, were about 7-feet wide, enough to accommodate a coal cart and a miner standing next to it. Haulageways led to entries, which led to “rooms,” the area where the miners attacked the coal face. Miners worked in teams of two in a 20-foot wide area at the coal face. At any one time, several dozen teams of miners were working at all compass points of the mine.

Coal seams at the Simpson Mine ranged from about 6 feet deep to over 14 feet. Rooms sometimes covered an area the size of a football field, although most of the overburden had already collapsed into the void after the coal was removed.

Haulageways also channeled the influx of fan-driven air from the surface which helped dissipate any explosive CH4 gas that might collect. Brattice clothes and a network of wood doors helped channel the airflow to the coal face.

The sinking of coal mine involved digging and blasting the equivalent of a 20 foot by 12 foot elevator rectangular shaft that bottomed out at a highly lucrative coal seam about 250 feet underground. Shafts were generally located in the middle of an area encompassing a mineral lease. Some leases covered as little as 30-50 acres, while other covered up to 320 acres or a half section of land.

The Simpson Mine, which operated from 1889 to 1926, spanned the length and breadth of original Lafayette on land owned by town founder Mary Miller and her brother, James B. Foote.

Starting in 1910, coal mines were required by the State of Colorado to submit on a regular basis maps showing where coal had been removed. Called “progress maps,” the maps showed the mine’s horizontal underground workings and included entries, rooms, shaft location and mine ventilation details.

The mine’s coal workings almost never followed a true north-south orientation. Instead, the coal seam determined the mine’s underground orientation.

Since all coal seams are on an incline, the mine engineer first determined the seam’s dip — the compass point at which the seam exhibits declination from the horizontal. The compass point at which the coal seam exhibits no declination was called the strike. This means the dip compass point and the strike compass point were offset by 90 degrees.

As observed in the progress maps, the mine oriented its main haulageway on the strike or “level course,” which allowed coal cars to move on level ground for great distances.

Entries or crosscuts off the haulageway that accessed rooms were mined at a right angle orientation to the strike, which meant that — moving from room to room or room to the haulageway — the coal car was either going slightly uphill or slightly downhill.

The room itself, where the bulk of coal was mined, was oriented and mined at the same compass point as the strike, so that the mining process was relatively level.

Underground, the layperson envisions the classic straight and level mine operation with straight line visibility from the elevator to the coal face being worked. Such was not the case, said Lafayette resident and retired mine inspector Louis Gaz in a 2015 interview. “A typical coal seam wasn’t level. It often undulated much like a river bed, up and down,” he said. “Most of the tracks used to haul the coal followed those ups and downs.”