Geology

Basin Gulch geology: near-surface, oxide-hosted gold and silver

Last updated: November 2026Published by Lannister Mining

What kind of gold deposit is Basin Gulch?

Basin Gulch hosts near-surface gold-silver mineralization in oxides, according to Lannister Mining.

Lannister Mining reports that Basin Gulch mineralization is open at depth, along strike and untested regionally. Several historical intercepts start at surface, including 0.66 g/t Au over 326 meters, which the company says gives significant flexibility for future mine design optimization.

The geology in four cards

Definition: oxide-hosted mineralization

Oxide-hosted mineralization is metal held in rock that has been weathered and oxidized, typically near the surface. At Basin Gulch, Lannister Mining describes the gold-silver mineralization as hosted in oxides and near surface. In general, oxide material is softer than unweathered sulfide rock and its gold is often more readily recovered, which is why explorers pay close attention to oxide zones. Recovery at any specific deposit is confirmed by metallurgical test work, not assumed from the rock type alone.

Near surface, from the first meter

Three of the five highlight drill intercepts Lannister Mining reports start at surface: 1.8 g/t Au over 162 meters, 0.66 g/t Au over 326 meters and 3.2 g/t Au over 72 meters. Mineralization that begins at surface means less waste rock sits above it, which is the basis for the company view that Basin Gulch offers mine design optimization flexibility.

Open in several directions

Drilling has not closed off the mineralization. Lannister Mining states it is open at depth, below the deepest holes, and along strike, the direction the mineralized trend runs. The wider region of the property is described as untested, and two-thirds of the property is still unexplored.

A district with a mining record

Basin Gulch lies in the Philipsburg Mining District, which led the original United States silver boom in the late 1800s. Montana as a whole has produced gold, silver, copper, nickel and platinum since the first territorial gold discovery at Gold Creek in 1852.

Basin Gulch geology in numbers

longest historical drill intercept, from surface (0.66 g/t Au): 326 m
highest-grade historical drill intercept, over 3 m: 156 g/t
silver in a historical trench, with 5 g/t Au over 34 m: 54 g/t Ag

How do near-surface and deeper intercepts at Basin Gulch compare?

Basin Gulch shows both broad, lower-grade zones from surface and narrow, higher-grade intervals. Both matter: broad zones can support bulk tonnage, while high-grade intervals can lift average grade.

Basin Gulch historical drill intercepts grouped by style, as reported by Lannister Mining
Style	Reported intercepts	What it suggests
Broad, from surface	0.66 g/t Au over 326 m; 1.8 g/t Au over 162 m; 3.2 g/t Au over 72 m	Thick mineralized zones starting at surface
Narrow, higher grade	156 g/t Au over 3 m; 25 g/t Au over 14 m	Higher-grade intervals within the system

Interval lengths are drilled lengths and may not equal true widths. For regional geology, the Montana Bureau of Mines and Geology publishes maps and reports for the state.

Common questions

What type of gold mineralization is at Basin Gulch?

Basin Gulch hosts near-surface gold-silver mineralization in oxides, according to Lannister Mining. Several historical drill intercepts started at surface, including 0.66 g/t Au over 326 meters and 3.2 g/t Au over 72 meters. Lannister Mining says this near-surface position implies significant flexibility for future mine design optimization.

More in the Basin Gulch FAQ

What does oxide-hosted gold mean?

Oxide-hosted gold sits in rock that has been weathered and oxidized, usually close to the surface. In general, oxide material is softer and its gold is often easier to recover than gold locked in unweathered sulfide rock. Basin Gulch mineralization is described as hosted in oxides; metallurgical testing is how any specific recovery is confirmed.

More in the Basin Gulch FAQ

What does open at depth and along strike mean?

It means drilling has not yet found the edges of the mineralization in those directions. Open at depth means it continues below the deepest holes; open along strike means it continues sideways along its trend. Lannister Mining states that Basin Gulch mineralization is open at depth, along strike and untested regionally.

More in the Basin Gulch FAQ

What does g/t Au mean in drill results?

g/t Au means grams of gold per tonne of rock. A result such as 1.8 g/t Au over 162 meters means the rock across that 162 meter length averaged 1.8 grams of gold per tonne. Ag is the symbol for silver. Lengths are drilled lengths, which are not always the true width of the mineralized zone.

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Does Basin Gulch have high-grade gold?

Historical results at Basin Gulch include high-grade intervals. Lannister Mining reports a historical drill intercept of 156 g/t Au over 3 meters and another of 25 g/t Au over 14 meters, alongside longer, lower-grade intercepts from surface such as 0.66 g/t Au over 326 meters. All are historical results that future drilling is planned to confirm.

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What mining district is Basin Gulch in?

Basin Gulch is in the historic Philipsburg Mining District of west-central Montana. Lannister Mining notes that this district led the original United States silver boom in the late 1800s. The property has year-round road access from the town of Philipsburg and is about one hour from Butte.

More in the Basin Gulch FAQ

How we chose these facts

This page was written by Lannister Mining, the company exploring Basin Gulch and the publisher of this site. Property figures are taken from Lannister Mining published materials and are stated exactly as reported, with historical results labeled as historical. General explanations describe common mineral exploration practice. Read the full methodology.

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