New York Hill Mine (New York Hill vein; North Star vein), North Star group, Empire Star group (Empire Star Mines Company holdings), Grass Valley, Grass Valley Mining District, Nevada County, California, USAi

Regional Level Types
New York Hill Mine (New York Hill vein; North Star vein)	Mine
North Star group	- not defined -
Empire Star group (Empire Star Mines Company holdings)	Group of Mines
Grass Valley	Valley
Grass Valley Mining District	Mining District
Nevada County	County
California	State
USA	Country

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A former lode Au-Ag occurrence/mine located in the NE¼ sec. 3, T15N, R8E, sec. 33 and in the SW¼ sec. 34, T16N, R8E, about 2½ km (1.5 miles) SSW of Grass Valley proper (about ¾ mile S of Grass Valley line), on private (patented) land. Discovered in 1852. The property comprises 54.34 acres. MRDS database stated accuracy for this location is 1,000 meters. The location point selected by the USGS for latitude and longitude represents the New York Hill Mine symbol on Lindgren's 1896 1:14,400-scale Grass Valley Special Map (contained in Lindgren's 1896 Nevada City Special Folio) and transcribed onto the USGS Grass Valley 7.5-minute quadrangle.

This was the first producer in the county. The New York Hill vein was one of the earliest to be mined in the district. The early work on the vein was done through the Chevanne and New York Hill shafts. On the 400-foot level, the vein was followed for 2,000 feet on the strike. It was stoped for 600 feet down dip in the Chevanne workings and 1,300 feet down dip in the New York Hill shaft. Between 1852 and 1865, it produced $500,000, and in 1866-67, 2,189 tons of ore yielded $106,430, an average of $49 per ton. Shortly thereafter, mining was suspended. Mining resumed in 1874 when it was reopened by means of a tunnel from Wolf Creek. The vein produced $100,000 between September 1874 and October 1875. In 1882, ore averaged $25/ton. In 1894, the North Star Mine purchased the New York Hill Mine. After about 6,000 tons of ore were removed, the mine was again closed and had not been reopened as of the late 1930s (Johnston, 1940). It is estimated that the New York Hill Mine produced about $1,500,000 from 100,000 tons of ore before closure. In 1929, the Newmont Mining Co. purchased a controlling interest in the North Star properties, which were consolidated with their Empire Mine as the Empire-Star Mines Co., LTD.

Mineralization is a vein deposit (Mineral occurrence model information: Model code: 273; USGS model code: 36a; Deposit model name: Low-sulfide Au-quartz vein; Mark3 model number: 27), hosted in Early Cretaceous granodiorite and Mesozoic-Paleozoic diabase. The ore body is tabular. Controls for ore emplacement included mineralization that occurs as erratic shoots within mesothermal gold-bearing quartz deposited within fracture zones. Local alteration includes ankeritic, sericitic, and pyritic replacement of wall rocks adjacent to veins. Local rocks include Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains).

The New York Hill vein strikes N 55? W and dips an average of 33? NE. The vein belongs to the North Star system of veins that produced in the famous North Star Mine located to the south.

In general, the New York Hill vein is more uniform in width and structure and has fewer splits and divergent walls than either the North Star or other veins in the North Star vein group. In the older shallow workings, the thickness of the vein ranged from 8 inches to 2 feet, but swelled to as much as 3 feet on the 600-foot level. The quartz is subhedral, in places has comb structure, and shows little evidence of shearing. In the lower levels, the vein fracture is generally narrow, and the average width of the quartz-vein filling is 6-12 inches, with a maximum of 24 inches. The outline of the ore shoots are shown in Johnson (1940, pl. 30). In the upper stopes, the quartz contained 2-3 percent sulfides, which yielded 4-5 ounces ($80-$100) of Au per ton. Most of the gold was free and much of it was coarse specimen gold. Below the 600-foot level, the quartz was too narrow to allow profitable mining.

Regional geologic structures include the Wolf Creek Fault Zone, Gillis Hill Fault and the Melones Fault Zone.

Workings include underground openings. Portions of the New York Hill underground workings through 1940 are shown in Johnson (1940, fig. 53 and pl. 30).

Ore materials include free-milling coarse and fine gold in quartz (850 fine) plus auriferous pyrite and galena. Gangue materials include quartz, calcite, chalcopyrite and sphalerite.


Production: This mine was the first producer in the county, producing $1,500,000 (period values) from 100,000 tons of ore.

It was estimated that the New York Hill Mine produced $1,500,000 (period values) from 100,000 tons of ore between 1852 and its closure in 1894.

Mineral List

10 valid minerals.