The first to really take advantage of the unique geology deep within the canyon were the magnesite miners of 1916. World War I had begun and there were only a few places in the U.S. where magnesite, needed for the war effort, could be mined, and it was found deep within Del Puerto Canyon.Once located, engineers quickly began grading a path up the canyon for the narrow gauge Patterson and Western Railroad to traverse up to Jones Station, where the ore could be hauled out for processing. They avoided the challenge of traversing Del Puerto Canyon’s narrow entrance by accessing the canyon from adjacent Black Gulch Canyon to the south.
From there, the natural path through the mountains created by Del Puerto Creek’s erosion was used to create the gradually ascending railroad grade to the magnesite mines. Utilizing Black Gulch Canyon (currently the I-5/Sperry Road interchange) also had its advantages because of its proximity to the recently incorporated City of Patterson, where the Sperry Road processing facility accessed the Southern Pacific Railway via a rail spur connecting to the narrow gauge railway.
By 1920, a few years after the end of the war, magnesite mining was no longer profitable, and by 1921 the two locomotives of the narrow gauge Patterson and Western Railroad were sold off to logging operations. When the rails of the railway were removed, a perfectly graded road bed was left where current day Del Puerto Canyon Road exists.
There are a few places where the road deviates from the historic Patterson and Western Railroad bed. Most of these locations are still visible within the first few miles of the canyon and would be inundated by the proposed Del Puerto Reservoir.