Metal Mines License Tax


Metal extractors in Montana must file a Metalliferous Mines License Tax (Form MML) return.

Tax Rates

The metal mines license tax is based on the gross value of the product and is applied to the payment the mining company receives from metal traders, smelters, roasters, or refineries.

The metal mines license tax only applies to gross values over $250,000.

Gross values under $250,000 are subject to the Resource Indemnity and Ground Water Assessment Tax (RIT).

Shipment TypeTax Rate
Dore, bullion, or matte1.6%
Concentrate or crude ore1.81%
Gold, silver or any platinum-group metal that is dore, bullion, matte, or other form of processed concentrate that is processed in a treatment facility owned or operated by the taxpayer and that is sold or shipped to a refinery for final processing

Determining Gross Value

Determine the gross value by multiplying the quantity of metal received by the trader, smelter, roaster, or refinery by the quoted price for the metal, then subtract allowed expenses.

(Quantity of Metal x Quoted Price) - Allowed Expenses = Gross Value

Allowed Expenses

You may subtract the contract costs. These are payment deductions specified in the contract between the mining company and the metal trader, smelter, roaster, or refinery.

These are:

You may also subtract the cost of shipping from the mine or mill to the smelter, roaster, or refinery.

Reporting and Payment Options

File and pay through our TransAction Portal (TAP).

Due Dates

The tax is due twice each year:

Period Ending June 30August 15
Period Ending December 31March 31

Penalties and Interest

The Metal Mines License Tax is subject to uniform penalties and interest.

Revenue Distribution

Revenue from the Metal Mines License tax is distributed:

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