After good-quality coal was discovered on the Green River in July 1880, the Black Diamond Coal Mining Co. of California began discretely buying up land. Henry Villard's Northern Pacific Railroad and its subsidiary the Oregon Improvement Co. also wanted the coal in this area. Villard planned to extend the Columbia and Puget Sound Railroad from Renton up the Cedar River. The Northern Pacific aggressively pursued financing for the extension, but the economic downturn after 1883 forced the railroad to solicit $150,000 in subsidies from Seattle businessmen. The Columbia and Puget Sound line was extended up the Cedar River to Black Diamond and from there to Franklin.
The railroad allowed the construction of coal mines at Cedar Mountain (1884), Franklin (1885), Lawson, and Ravensdale (1900). The Green River field added to production from Renton and Newcastle. Most of the coal was shipped to San Francisco.