Mining Ruins, Wickenburg, Arizona
Gold Bar or O'Brien Mine
We took a Sunday drive on Constellation Road near Wickenburg to explore the Gold Bar Mine and its ruins. The road appeared a little smoother then I remembered when exploring the Monte Cristo Mine, but I would still recommend a high clearance vehicle or a 4x4. There are a few locations where you cross river beds and could get stuck with little to no cell service. In order to explore the mining ruins it requires a hike on terrain that is rocky with tons of obstacles you could easily get injured on.
The Gold Bar or O'Brien mine is 15 miles by road northeast of Wickenburg and 2.7 miles northeast of Constellation. This deposit was located in 1888 by J. Mahoney. About 1901, the Saginaw Lumber Company erected a 10-stamp mill on the property and is reported to have treated 4,000 tons of ore that yielded about $60,000.
In 1907-1908, the Interior Mining and Trust Company is reported to have mined the ore body from the surface to the 385-foot level on the incline. This company erected a 100-ton mill, equipped with stamps, amalgamation plates, tables, and vanners. Heikes states that the 1907 production amounted to $33,402 in bullion and concentrates. These concentrates averaged, per ton, 2 ounces of gold, 3 ounces of silver, 49 per cent of iron, 15 per cent of silica, and 15 per cent of sulphur. He also states that, in 1908, $91,749 worth of gold came from the Black Rock district of which the largest producer was the Interior Mining and Trust Company.
About 1915, the company was reorganized as the Gold Bar Mining Company and a vertical shaft was sunk to the 700-foot level. In February, 1934, the property was under the trusteeship of the commonwealth Trust Company, of Pittsburg, and was being worked in a small way by lessees. This region has been deeply dissected by northward-flowing tributaries of Hassayampa Creek. The principal rock is mediumgrained granite, with some inclusions of schist. It is intruded by pegmatite, granite-porphyry, and basic dikes. Fissuring in N. 70° E. and S. 30° E. directions is evident.
The vein, which outcrops on the western side of O'Brien Gulch, at an altitude of 3,400 feet, occurs within a fissure zone that strikes N. 70° E. and dips 30° NW. Its filling consists of coarsely crystalline, glassy, grayish-white quartz. In places, the quartz from the oxidized zone is rather cellular with cavities that contain abundant hematite and limonite formed from pyrite. Pyrite is present in the deeper workings. The gold occurs as fine to mediumly coarse particles, both in the quartz and with the iron minerals. The wall rock shows intense sericitization. The mine workings indicate that the ore shoot was a chimney that measured about 40 by 50 feet in cross-section at the surface and plunged 30° SW.