Data Methodology

This page documents how MinesNearMe.com collects, processes, and serves mine location data. If you are citing this data in academic research, journalism, or policy work, please reference this page and the original federal sources described below.

Data Sources

USGS Mineral Resources Data System (MRDS)

The primary geological dataset. MRDS is maintained by the U.S. Geological Survey and contains records of mineral deposits, mines, prospects, and occurrences across the United States. We import records that have verified U.S. coordinates (non-zero latitude/longitude and country = "United States"). Our database includes 266,593 MRDS records.

MRDS provides: site name, coordinates, county, up to three commodities, operational type (surface/underground), development status, deposit type, and production year ranges.

Source: mrdata.usgs.gov/mrds/

MSHA Mine Safety and Health Administration

The operational dataset. MSHA maintains records of all mines subject to the Federal Mine Safety and Health Act of 1977. This includes active operations, intermittent mines, and historical records of abandoned or sealed sites. We import all records with valid coordinates. Our database includes 47,323 MSHA records.

MSHA provides: mine name, coordinates, state, county, primary commodity, mine type, operational status, operator name, employee count, and nearest town.

Source: MSHA Open Government Data

Processing Pipeline

1. Download — Raw data files are downloaded from USGS (CSV) and MSHA (pipe-delimited text).
2. Filter — Records without valid U.S. coordinates are excluded. MRDS records outside the United States are excluded.
3. Normalize — Field names are mapped to a common schema. State names are standardized. County names are cleaned.
4. Deduplicate — MRDS and MSHA records are stored separately with a composite unique key (source + source_id). There is no cross-source deduplication — the same physical mine may appear in both databases with different attributes. This is intentional: MRDS provides geological context while MSHA provides operational data.
5. Summarize — Aggregate tables are built for state-level, county-level, and commodity-level statistics using SQL aggregation.

Coordinate Accuracy

Coordinate accuracy varies significantly between sources and records:

• MSHA active mines — Generally accurate to within a few hundred feet. These coordinates are provided by mine operators and verified by MSHA inspectors.
• MSHA historical mines — Variable accuracy. Older records may use section-center or town-center coordinates.
• MRDS mines — Highly variable. Modern records may be GPS-accurate. Historical records (especially pre-1970s) may be placed at the nearest town, section center, or county centroid. Always verify on the ground before relying on precise locations.

Known Limitations

• The same physical mine may appear in both MRDS and MSHA with slightly different names, coordinates, and attributes.
• Historical mine coordinates should be treated as approximate. Some may be miles from the actual site.
• Commodity names are not fully standardized between MRDS and MSHA. "Coal (Bituminous)" in MRDS may appear as "Bituminous Coal" in MSHA.
• MRDS status fields ("Past Producer", "Producer", "Prospect") reflect geological assessment, not current operational status. Use MSHA status for current operations.
• Not all U.S. mines appear in these databases. Small operations, very old mines, and some state-regulated mines may be absent.

Update Schedule

MSHA publishes updated data weekly. USGS MRDS is updated periodically. Our database is rebuilt from the latest sources on a regular basis. The most recent build date is: 2026-04-01.

Citation

If you use this data in research or publications, we suggest the following citation format:

MinesNearMe.com. (2024). U.S. Mine and Mineral Deposit Database. Compiled from USGS Mineral Resources Data System and MSHA Mine Data Retrieval System. Retrieved from https://minesnearme.com/methodology

Downloads

State-level CSV downloads are available from each state page, or directly via:

/api/download/{state-slug}.csv — e.g., /api/download/california.csv

For programmatic access, see our free JSON API documentation.