Manchester, Monterey County, California

Before the arrival of Cruickshank and other Western miners, Chinese miners produced a small quantity of gold from the gravel bed of the San Antonio River near Jolon, and small amounts of placer gold from the coastal ravines of the Santa Lucia Range.[8]

William T. Cruikshank, born in Troy, New York, arrived in California with his father Arnold in 1849. William and his wife Sarah Ann (nee French) were living in Contra Costa County in 1867.[9] Their son William Dugay Cruikshank was born in Fresno County in 1855. The father and son moved to the Manchester area in 1872.[10][9] They searched for gold along with others. At a miner's meeting on February 5, 1875, the Los Burros Mining District was organized. H. C. Dodge was elected Chairman, A.C. Frazier, Secretary, and William T. Cruikshank Recorder.[6] During the next 12 years, 131 mining claims were recorded.[6]

The most valuable gold discovery was made by William Dugay Cruikshank, on March 24, 1887, who called his find the Last Chance mine. The Last Chance mine eventually was 450 feet (140 m) long and dug to a depth of 150 feet (46 m). Cruickshank found five veins which milled at an average of $200 per ton.[10]^: 84 During the first year of the mining district, 63 claims were recorded. In 1889 the Manchester Mine was dug about 60 feet (18 m) into the mountain; the Melville Mine had a tunnel about 110 feet (34 m) long.[11]

Eventually around 500 claims existed. Many Los Burros mines were registered and renamed, likely filed under several different names. Placer claims were filed along Plaskett Creek, Willow Creek and tributaries, and Alder Creek.[7] Cruikshank, who partnered with James Krinkle, shipped an estimated $62,000 in gold ore from the Last Chance Mine.[12] Since there was no road into the area, the crushed gold ore was sacked and transported on donkeys (hence, los burros) over the Santa Lucia Mountains to the Nacimiento River. From there they were hauled on sleds by mules over about 4 miles (6.4 km) over steep, uphill terrain to the mines.

There was a dog-hole landing south of San Martin Rock near the Plaskett Ranch where mining equipment like the ore crushers and stamp mills were brought by ship.[13] Mules were used to haul the machinery 8 miles (13 km) up the ridge.[14] Cruickshank built hoisting works and a 10-stamp mill which began operating on November 29, 1889.[15][16]

Another flurry of activity occurred in the early 1900s when placer gold was discovered in gravel and alluvial deposits along various forks of Willow Creek. The entire Willow Creek watershed was prospected, and a large number of pits, shafts, tunnels, open cuts, and adits were explored by miners.[7] The mines were not very productive, and most mining activity ceased by about 1895. Between 1900 and 1909, another 322 claims were filed there.[5] Intermittent small-scale prospecting and development work have continued in the district until the present time. There was a recorded production of several hundred dollars worth of gold in 1953 and again in 1963. Over 2000 mining claims were located in the district.[17][13] As of 2023, there were eight active claims..[18]

Dark sandstone is most abundant and is also the chief host rock of the gold-bearing deposits. Also present are chert, shale, serpentine, and volcanic rocks. Most of the gold has been recovered from small lenticular ore shoots in oxidized zones near the surface. The sulfides, which consist of fine-grained pyrite and small amounts of chalcopyrite and arsenopyrite generally, are low in gold content. Most of the placer gold has come from Willow Creek, and much of it was concentrated as coarse ragged fragments. Very small amounts have been found in Alder, Plaskett, and Salmon creeks.[17]

The mining occurred in three nearly parallel quartz veinlets, parallel to a layer of sandstone. The gold was removed via open cuts, shafts, and drift tunnels. The Last Chance reached a maximum depth of 160 feet (49 m). In 1902, large gold nuggets were found on Spruce Creek and placer gold was found in Willow Creek. Ancona, Buclimo $62,000; Bushnell, Gorda, Grizzly, Mariposa, Melville, New York, Plaskett (placer) $18,000; Spruce (placer) $22,000. The value of the total output is estimated to be about $150,000 (or about $2,556,000 today).[3]^: 326

A fire destroyed the town in late 1890. Portions were rebuilt, but by 1895 the boom had begun to fade.[24] The Mansfield post office closed in 1897. [10]^: 46

Additional fires destroyed most traces of the town with the exception of the remnants of the stamp mills. In September 1970, the Buckeye fire burned through most of the Los Burros Mining District and destroyed nearly all of the remaining miners shacks and cabins. The US Forest Service later destroyed any that remained.[25]

In mid-December, 1937, it was discovered that 81-year-old William D. "Billy" Cruikshank had not been seen since November 16. Billy went missing while traveling the trail between his cabin in Manchester and Jolon. The sheriff organized a posse on December 15 to look for him.[26] His body was never found.[27][28] The Cruikshank Trail, Lower Cruikshank Camp, and Upper Cruikshank Camp in the Silver Peak Wilderness are named for him.[29]