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In the spring of 1859, after digging down to a depth of about ten feet, they found a gold-rich reddish quartz vein. Their discovery was actually part of the Comstock Lode, the Old Red Ledge. [ 2 ] : 5–6 The four men are therefore credited with the rediscovery of the mine previously found by the Grosh brothers.
Quartz reef breaking the surface at Paynes Find, Western Australia. Quartz reef mining is a type of gold mining in "reefs" (veins [1]) of quartz.Quartz is one of the most common minerals in the Earth's crust, and most quartz veins do not carry gold, but those that have gold are avidly hunted by prospectors.
In situ gold-bearing vein (in brown) at the Toi gold mine, Japan. In many gold mines exploited during the gold rushes of the 19th century, vein material alone was typically sought as ore material. [8] In most of today's mines, ore material is primarily composed of the veins and some component of the wall rocks which surrounds the veins. [9]
Quartz is generally the dominant mineral in the veins, but there are also gold bearing carbonate dominant veins in orogenic deposits. [15] Ore bodies of orogenic gold deposits are generally defined by ≤ 3–5% sulfide minerals, most commonly arsenopyrite in metasedimentary host rocks and pyrite /pyrrhotite in meta-igneous rocks, and ≤ 5 ...
The Monte Cristo Gold Mine (Spanish for Mountain of Christ Gold Mine) is a gold mine in the San Gabriel Mountains near Los Angeles, California, USA. The Monte Cristo Gold Mine is part of the quest for mineral wealth in the San Gabriels. Many of the older tunnels and shafts are closed, and the 100-year-old machinery is no longer in operation.
China says it has discovered the world’s largest known deposit of gold, estimated to be worth over $80bn (£63bn).. The deposit at the Wangu goldfield in central China could yield more than ...
High-grade gold ore from the Harvard Mine, Jamestown, California, a wide quartz-gold vein in California's Mother Lode. Specimen is 3.2 cm (1.3 in) wide. Various theories of ore genesis explain how the various types of mineral deposits form within Earth's crust. Ore-genesis theories vary depending on the mineral or commodity examined.
Gold ore deposits reside in the quartz veins, ranging from 3 to 7 ounces per ton. The Empire Vein outcrops to the east on a north–south strike, dipping at a 35-degree angle to the west. The vein was mined with inclined shafts following dip, with horizontal shafts (drifts) every 300–400 ft (90–120 m) along strike. The ore was mined by stoping.