About

Rock Sources is a beta atlas of US construction-materials facilities: aggregate operations (crushed stone quarries and sand & gravel pits) and asphalt (hot-mix) plants. Everything shown is derived from public government records.

Where the data comes from

• Aggregates (nationwide) — the US Mine Safety and Health Administration (MSHA) mines dataset, deduplicated so related records for one physical operation appear as a single facility. This site uses U.S. Department of Labor data but is not endorsed or certified by the DOL.
• Asphalt plants (state by state) — official state producer lists, such as state DOT–approved asphalt producer directories. Kentucky listings derive from the KYTC Division of Materials List of Approved Materials; California from the Caltrans Material Plant Quality Program; Maryland from the MDOT State Highway Administration approved asphalt producers report; Massachusetts from the MassDOT qualified hot-mix asphalt plant list; Mississippi from the MDOT Production Facilities report; Ohio from the Ohio ODOT Approved Asphalt and Concrete Plants report. No state DOT endorses or certifies this site. Coverage grows as additional states are connected.
• Plant coordinates (where shown) — state environmental agency GIS records: Arkansas Department of Environmental Quality (via the Arkansas GIS Office), the NJDEP Geographic Information System (GIS), and Delaware DNREC Air Permitted Facilities via FirstMap. This map was developed using New Jersey Department of Environmental Protection Geographic Information System digital data, but this secondary product has not been verified by NJDEP and is not state-authorized or endorsed. FirstMap data is provided as-is; each mapped Delaware coordinate was individually adjudicated for this atlas and is not agency-verified. Alabama coordinates derive from Alabama Department of Environmental Management AEPACS permitted-activity records; each mapped Alabama coordinate was individually adjudicated for this atlas against public aerial imagery and is not agency-verified. Two Rhode Island aggregate facilities are plotted at their EPA ECHO / ICIS-NPDES permit-record coordinates (RIDEM RIPDES permits), individually adjudicated for this atlas; these are permit-record points, not surveyed locations. Ohio coordinates derive from the Ohio Environmental Protection Agency, Division of Surface Water — Industrial Stormwater (NPDES) permits point layer (applicant-reported facility points; Ohio EPA notes that inconsistencies and inaccuracies may exist across time periods); each mapped Ohio coordinate was individually adjudicated for this atlas against public USGS aerial imagery and is not agency-verified. Maryland coordinates derive from the Maryland Department of the Environment, Air and Radiation Administration — Air Emissions Facilities point layer (agency-published points with undocumented lineage); each mapped Maryland coordinate is the plant location an adjudicator placed on public USGS aerial imagery near the agency point, and is not agency-verified.
• Curated additions (facilities MSHA misses) — a small number of receipted aggregates facilities come from other public records: Vermont ANR Stormwater Permits (Issued Permits) via the Vermont Open Geodata Portal (license stated by the publisher as CC BY-SA, version unspecified; Vermont pins show the ANR registry point, a permit-registry location that is not agency-surveyed), Sussex County, Delaware council records, Delaware DNREC public notices, State of Rhode Island (RI.gov) press releases, and — for New Hampshire, Vermont, and Rhode Island, where MSHA registers no asphalt plant — EPA ECHO air facility records (NHDES, Vermont DEC, and RIDEM air permits as carried in ICIS-Air; public-domain U.S. Government data; listing there is not an operating-status claim by this site). ECHO facility points are EPA address-matched or reported locations, not surveyed; an ECHO-sourced coordinate is shown only after individual adjudication against public aerial imagery for this atlas and is not agency-verified — today New Hampshire and one Vermont plant have such adjudicated points; the other Vermont ECHO records and Rhode Island are listed without a map position. A handful of MSHA records with erroneous published fields (out-of-state points, wrong county labels) are corrected or unmapped with receipts; each correction is documented in the release notes.

Coverage — what absence means

Aggregate coverage is national because MSHA enumerates those operations federally. Asphalt plants appear only where a state producer list has been connected, so a state with no asphalt plants shown has not been covered yet — that is not a claim it has none.

Status semantics

Aggregate facilities carry the operating status their MSHA record reports (active or intermittent). Asphalt plants are shown as “listed” — a producer list documents membership on the list, not day-to-day operating status.

Versioning and accuracy

Data ships in versioned, immutable releases; the map always loads the current release. Each facility page shows how many sources support its accepted facts. The underlying records are maintained by their agencies and can be incomplete, outdated, or wrong; cross-source corroboration is ongoing and data may change between releases. You can report a correction or concern for private review.