Mule hauling coal out of Rock Springs coal mine, undated

Mining teams used hand picks to chip out narrow horizontal channels at the base of the coal seams and then drilled holes into the seams and inserted tubes of black powder. The fuses were lit, the powder exploded, and chunks of coal dropped. The coal was then loaded into cars, pulled to the entry shaft by mules, and lifted up the shaft to the surface for weighing and transfer to railroad flats.