The Saddle deposit is of sheeted vein type; it trends northeasterly from near the west portal of the Miocene Ditch tunnel nearly to the top of hill 691. Other gold-bearing veins were developed in the south fork of upper Snow Gulch. One prospect in this group appears to lie on the Bernice No. 1 lode of John Leedy (U.S. Mineral Survey No. 775); the New Era tunnel is also in this vicinity. Another related vein zone possibly exists on the divide between Snow Gulch and Anvil Creek, nearly in line with the trend of Snow Gulch.

Prospecting dating back to at least 1899 has identified several gold lodes near the head of Snow Gulch. The older prospects, such as New Era and Big Four, are difficult to identify, but they can be approximately located. These vein and stratabound mineral occurrences are abundant in upper Snow Gulch and appear to be the main source of placer gold in Snow Gulch.

A prospector named John Leedy located claims on the east side of Snow Gulch and on Bonanza Hill from July 1899 until 1908; his claims were patented in 1908 (U.S. Mineral Survey No. 775). A stamp mill was moved into this area and various tunnels and workings were driven, including the New Era tunnel, reported to be more than 300 feet long. The tunnel was driven on a lode that strikes northeast and dips 40 northwest (Chapin, 1914, p. 400-401). The gold is in pyrite and arsenopyrite. The sulfides are disseminated in schist that is cut by quartz, minor albite, and locally calcite veinlets.

The New Era tunnel which was caved when visited by Chapin, appears to be near Placer Dome trenches ST-88-06, -08 and -010. These trenches expose zones containing more than 0.1 ounce of gold per ton. Mertie (1918, p. 433-434) examined this area in 1916. He repeated Chapin's description of the New Era tunnel, but was able to examine the Big Four shaft. He reported that this shaft was on the east side of Snow Gulch at an elevation of about 500 feet. Quartz stringers in a 60-foot-wide zone in marble strike about N 65 E and contain crystalline gold in vugs in quartz. This area was also described by Cathcart (1922, p. 243-244).

The Saddle deposit, mainly explored between 1986 and 1995, appears to start west of the portal of the Miocene Ditch tunnel and to continue northeasterly for about 1,300 feet. This deposit has been explored by shallow trenches and drill holes. It is irregular but is as much as 200 feet wide. The Saddle deposit is less consistently mineralized than the Rock Creek sheeted zone (NM207), but a small body of material averaging about 0.05 ounce of gold per ton has been identified, and probably more could be developed. Other trenching and shallow drilling suggest that gold-bearing veins are also present in a west-southwest-trending zone west of the portal of Miocene tunnel. The apparent strike length of the zone is about 1,200 feet. This zone probably includes the New Era deposit.

An isolated deposit, about 1,200 feet northeast of Saddle, was found by Newmont in 1992, and a deposit at the ridge between Snow Gulch and Anvil Creek was intersected in three Placer Dome trenches (ST-88-3, -4, and -5). The deposit in these trenches can be projected about 300 feet on strike.

Bedrock in the area is schist and some marble, probably of early Paleozoic protolith age (Hummel, 1962; Sainsbury, Hummel, and Hudson, 1972; Till and Dumoulin, 1994; Bundtzen and others, 1994). Strata exposed in upper Snow Gulch and continuing southward on Bonanza Hill are chloritic mica schist, marble and occasional graphitic units. In general they belong to the chlorite-rich metaturbidite schist and marble unit of Bundtzen and others (1994).

Lode prospects were located in this area as early as 1899; there was considerable lode prospecting activity until World War I. n the mid-1980', R.V. Bailey discovered the Saddle deposit and began a trenching program that identified a sheeted vein complex. This exploration was followed by an extensive trenching program and some drilling by Placer Dome in 1987 and 1988, by soil geochemistry and some drilling by BHP in 1990, by detailed mapping and some drilling by Newmont Mining Company in 1992, and by additional drilling by Kennecott Exploration Company in 1994-5.