First known as the Sedro Mine and also as the Bennett Mine in honor of the man who discovered the veins at this location, the Cokedale Mine was located about six miles east of Sedro-Woolley. The mine was operated intermittently from 1891 to 1922, with most of the coal being processed in the 50 coke ovens on the site. During those years, Cokedale had the only extensive quantity of excellent coking coal in the state. To generate temperatures needed to bake limestone, a key ingredient in cement, approximately 250 tons of coking coal were shipped daily to the old Portland Cement Company at Concrete . By the mid-1950s, the site had all but vanished. The only indications that there ever had been a mine there were the railroad grade, a refuse dump from the mine, and coal stains on the ground.

Cokedale, the settlement which housed the 75 workers and their families at the mine, (131 in 1900 census) was unique in Skagit County for its dreary ugliness and its disappearance left no mourners.
From Skagit Settlers: Trials and Triumphs 1890-1920

"A tunnel was driven into the mountain to a depth of 1,267 feet which intersected seven coal seams which were as narrow as a few inches wide to as much as 30 feet. There was also a vertical shaft that measured 550 feet deep. Production varied from a low of 1,000 tons a year to a high of 20,764 tons, or an average of 9,510 tons a year for each of the 19 operative years."
From Yarns of the Skagit Country - Ray's Writin's by Ray Jordan