Assessment Work
The annual labor or improvements, worth at least $100 per mining claim, that a claimant under the small miner waiver performs instead of paying the BLM maintenance fee.
Detailed Definition
Assessment work is the annual labor or improvement a claimant performs on an unpatented mining claim to hold it. The Mining Law requires that "not less than $100 worth of labor shall be performed or improvements made during each year" (30 U.S.C. 28). Today the requirement falls on claimants who hold their mining claims under a waiver of the maintenance fee. Everyone else pays the fee instead.
The amount
A claimant must spend $100 in labor or improvements for each mining claim for each assessment year, and the total must equal at least $100 per claim (43 CFR 3836.11).
The assessment year
An assessment year is the 12 consecutive months beginning September 1 (43 CFR 3830.5). Under the statute it begins at 12:01 a.m. on the first day of September following the date of location.
Work that qualifies
Under 43 CFR 3836.12, assessment work includes, but is not limited to:
- Drilling, excavations, driving shafts and tunnels, sampling, and road construction
- Geological, geochemical, and geophysical surveys
Limits on surveys
Surveys count only within the limits of 43 CFR 3836.14.
- A qualified expert, meaning a geologist or mining engineer qualified by education and experience, must conduct the survey and verify the results in a detailed report.
- The report must be recorded with BLM and with the local recording office.
- Surveys may not be counted for more than 2 consecutive years, or for more than a total of 5 years on any one mining claim.
- A survey may not repeat a previous survey of the same claim.
Filing the proof
A claimant who performs assessment work files an affidavit of assessment work with BLM on or before December 30 of the calendar year in which the assessment year ends (43 CFR 3835.31). BLM charges a processing fee for recording the annual filing, listed at $15 per claim for fiscal year 2026. Holders of mill sites and tunnel sites file a notice of intent to hold instead.
Who performs assessment work
The small miner waiver is limited to a claimant who, together with all related parties, holds no more than 10 mining claims and sites nationwide. The waiver certification is due on or before September 1. A claimant who files it must then perform the assessment work on time and file the annual document.
What happens when the work is not done
A mining claim on which the required work was not performed is open to relocation by a rival claimant as if no location had ever been made (43 CFR 3836.15). A claimant under waiver who does not file the annual document by December 30 forfeits the claim (43 CFR 3835.91).
In the record
An affidavit of assessment work is a claimant's own sworn statement. It shows that a filing was made on time. It does not by itself establish that the work was done, that it cost what is stated, or that it benefited the claim.
Related Terms
BLM (Bureau of Land Management)
The Bureau of Land Management, the Interior Department agency that manages the federal mineral estate and records and maintains unpatented mining claims and sites.
Unpatented Mining Claim
A mining claim on federal land for which no patent has been issued. The claimant holds a possessory right to the minerals and the United States keeps title to the land.
Mining Claim Maintenance Fee
The annual fee paid to BLM to hold an unpatented mining claim or site: $200 per lode claim, mill site, or tunnel site, and $200 per 20 acres of placer claim, due by September 1.
Small Miner Exemption
A waiver of the annual BLM maintenance fee for a claimant who, with all related parties, holds 10 or fewer mining claims and sites and performs annual assessment work instead.
Annual Filing
The yearly payment or documents required to hold an unpatented mining claim: the maintenance fee or a waiver by September 1, and in some cases an annual FLPMA document by December 30.