Black Diamond’s Mine No. 11

Black Diamond’s Mine No. 11
Black Diamond’s Mine No. 11

This is the third in a series of photos of Black Diamond’s Mine No. 11, named for the section of land in which it was located. Opened in 1896 it was originally called Morgan slope – in honor of Morgan Morgans, the mine’s superintendent. The slope dipped underground at a pitch varying 17 to 23 degrees off horizontal. The slope, from which coal was hauled out on small rail cars, proceeded down at that angle for over a mile. Those light-weight rail tracks can be seen to the upper left in the photo. The standard gauge tracks and rail cars below were loaded with processed coal from the bunkers for shipment to market. Vertically, the mine was 2,000 feet deep or 1,400 feet below sea level, reaching under the east end of Lake Sawyer. At each of the working levels from which coal was extracted, the mine extended north and south over a mile in each direction. Coal was mined from two benches of the McKay seam. It was also known as Franklin No. 14 in a series of 18 seams created during the Eocene epoch lasting from 34 to 56 million years ago. Coal was mined under a room and pillar system with certain areas fully extracted (called rooms) while adjacent pillars held up the roof from further collapse. Towards the end of the mine’s life these pillars were extracted (or pulled) as underground workings retreated up the slope collapsing mined out area below. Contrary to popular myth, the underground workings of this coal mine were mostly collapsed during the removal of pillars and intense weight from thousands of tons of overlying bedrock. This circa 1920 photo of Pacific Coast Coal Co.’s Mine #11 comes courtesy of the University of Washington Libraries, Special Collection No. UW-23730.