PENNSYRR.COM by Jerry Britton

"Carbon Colliery, also within the borough of Broad Top City, was opened in 1872, by the elder Mears, and it is still operated by his sons. The mouth of the drift is seven hundred yards from the railroad, which is reached by a tramway and a self-acting plane. This mine is nearly worked out, and will soon be abandoned."1
1History of Huntingdon and Blair Counties, Pennsylvania by J. Simpson Africa Philadelphia, PA: Louis H. Everts, 1883, pp. 228-237.