Located west of Locust Dale in Mt. Carmel Twp. Northumberland Cty., Penna. the colliery was opened by a slope sunk 330 ft.on the south dip mammouth vein by the Locust Dale Coal Company in 1867. The first shipment of 35,410 tons was made in 1868. The Locust Dale Coal Company conducted the operations of the colliery on their own lands and the officers were George Potts, President, Francis Jaques, Treasurer and Theodore D. Emory, Secretary. The company operated the colliery until 1871 driving the gangways westward to its boundary at the west land line and eastward to a fault.
In 1871, Franklin B. Gowan, President of the Philadelphia & Reading Railroad purchased the lands of the company. Stephen Harris was the agent and superintendent.
In 1873, the P&R C&I Co. took possession of the colliery and extended the slope to the second level, a total length of 884 ft.from the surface and sunk a new pump slope 180 ft. east of the mammoth slope to the first level. Powerful machinery was installed. Two new hoisting engines at the coal slope and one at the pump slope, with 20 new boilers 33 in. in diameter by 30 ft. long. The breaker was rebuilt and the old machinery replaced with more efficient appliances for the preparation of coal.
In 1874, a third slope was sunk to establish the depth of the basin and in 1877, the hoisting and pump slopes were extended to the third level, a total length from the surface of 1230 ft.
In 1877-78 they drove a tunnel 840 ft. south at a point 1050 ft. west of the coal slope with the intention of later to extend it across the basin to the north dip mammoth vein, which was completed at a distance of 3140 ft. in 1891.
In spring 1885, the breaker was destroyed by fire and was replaced with a larger one in Nov. 1885 with more modern machinery. The P&R C&I Co. continued mining on an extensive scale until Mar.31, 1897 when they abandoned the colliery, because it did not pay to operate. The total shipments from the Miriam Colliery was 2,769,938 tons.