MSHA DATABASEMSHA records · 17 contributing sources · snapshot Oct 13, 2026

MINE DETAILS

Decker Mine

ActiveSurfaceCoal (Bituminous)
MSHA MINE ID2400839
LOCATIONBig Horn, MT
PUBLIC RECORD5,236 linked rows

LOCATION

Mine location

1 of 1 mine with usable MSHA coordinates. Select a marker to open a mine.

Mine coordinates

2025-01-01 – 2026-10-13Applies to production, safety and portfolio metrics. Silica samples have separate filters.

Violations

12

1 significant & substantial (S&S)

  1. 2025 Q15
  2. 2025 Q22
  3. 2025 Q30
  4. 2025 Q41
  5. 2026 Q12
  6. 2026 Q20
  7. 2026 Q32
  8. 2026 Q4 *0

Accident records

1

0 records classified as fatality

  1. 2025 Q10
  2. 2025 Q20
  3. 2025 Q30
  4. 2025 Q40
  5. 2026 Q11
  6. 2026 Q20
  7. 2026 Q30
  8. 2026 Q4 *0

Proposed penalties · USD

2,479.00

12 of 12 violations with amounts

  1. 2025 Q11,422
  2. 2025 Q2302
  3. 2025 Q3—
  4. 2025 Q4151
  5. 2026 Q1302
  6. 2026 Q2—
  7. 2026 Q3302
  8. 2026 Q4 *—

On-site inspection hours

133.50

6 inspections · 6 with hours

  1. 2025 Q128.25
  2. 2025 Q219.75
  3. 2025 Q3—
  4. 2025 Q435.75
  5. 2026 Q118.25
  6. 2026 Q2—
  7. 2026 Q331.50
  8. 2026 Q4 *—
Quarterly safety data
QuarterViolationsS&SProposed USDAccident recordsFatality recordsInspectionsOn-site hours
2025-Q1511,422.0000128.3
2025-Q220302.0000119.8
2025-Q300—000—
2025-Q410151.0000135.8
2026-Q120302.0010218.3
2026-Q200—000—
2026-Q320302.0000131.5
2026-Q4 *00—000—

Most cited CFR sections

All violations issued in the selected period. Counts combine subsections.

Safety activity

  1. violation9607096

    77.1103(a) · $151.00 proposed

  2. violation9607095

    77.1110 · $151.00 proposed

  3. inspectionF003104

    Regular Safety and Health Inspection · 31.5 on-site hours

  4. inspectionF002D83

    Verbal Hazard Complaint Inspections · 6.8 on-site hours

  5. violation9733025

    77.704-8(a)(1) · $151.00 proposed

  6. violation9733024

    77.1110 · $151.00 proposed

  7. inspectionF009D9B

    Compliance Follow-up Inspection · 11.5 on-site hours

  8. accident220260370002

    HANDLING OF MATERIALS · DAYS RESTRICTED ACTIVITY ONLY

    Accident narrative

    Mechanic was under a dozer looking for a leak on the equalizer bar. Once the mechanic found the problem, EE went to crawl out from underneath the dozer EE used EE's arm to assist self in getting up. In this process EE's left shoulder dislocated from the socket.

  9. violation5038877

    47.41(a) · $151.00 proposed

  10. inspectionF03AAFF

    Regular Safety and Health Inspection · 35.8 on-site hours

  11. inspectionF010304

    Regular Safety and Health Inspection · 19.8 on-site hours

  12. violation9732255

    77.1607(p) · $151.00 proposed

  13. violation9732254

    77.502 · $151.00 proposed

  14. violation9731950

    77.502-2 · $151.00 proposed

  15. violation9731949

    77.502-2 · $151.00 proposed

  16. inspection6472808

    Regular Safety and Health Inspection · 28.3 on-site hours

  17. violation9732308

    77.502 · $151.00 proposed

  18. violation9732307

    77.1103(d) · $151.00 proposed

  19. violation9732306

    77.502 · S&S · $818.00 proposed

Safety sources and definitions

MSHA Violations (issue date), Accidents (accident date), and Inspections (begin date). Snapshot 2026-10-13.

Counts describe published rows, including contractor records; accident records are not distinct incidents or numbers of people injured.

Zero means no matching records in the imported sources, not proof of no events. Historical coverage differs by source; absence before a source begins reporting is not a zero incident rate. Invalid or absent dates and records after the snapshot are excluded.

S&S means SIG_SUB=Y. Fatality records use DEGREE_INJURY_CD=01. Proposed penalties are not final assessed or paid amounts; missing dollar values are omitted.

Inspection hours are SUM_TOTAL_ON_SITE_HOURS attributed to the inspection start date, without supervisor/trainee hours. Missing hours are omitted; a started inspection may still be open.

Portfolio totals use current mine membership, including events before the current owner or operator's tenure.

CFR headings link to the current Title 30 index; they are not historical legal determinations.

Latest EIA month: 2026-07Source checked 2026-10-13 · publication lag differs from MSHA.

REPORTED RECEIPTS · SHORT TONS—0 rows · 0 receiving plants
HEAT CONTENT · BTU/LB—Weighted by reported tons
SULFUR / ASH · % BY WEIGHT— / —Separate averages over measured receipts
DELIVERED COST · USD/TON—No price coverage

No receipts matched this mine in the selected period. EIA-923 does not cover all mine sales, exports or metallurgical coal shipments.

Coverage, sources and calculations
  • Reported coal receipts at EIA-923 power plants/terminals; this is not a census of mine shipments, exports or metallurgical sales.
  • Matches use only the published MSHA ID, normalized to seven digits. Unidentified mine origins remain in the source table but are not assigned to a mine.
  • Portfolio attribution uses current MSHA ownership, not ownership at the shipment date. Receipts and production can differ because of timing, stocks and coverage.
  • Quality means are weighted by positive reported tons with that measurement. Delivered cost uses only rows with published cost, positive heat and positive tons; missing/withheld costs are never zero-filled.
  • USD/ton = (cents/MMBtu ÷ 100) × MMBtu/ton. This is plant delivered cost, not mine sales price or revenue.
  • Receipt month is as published, including records supplied by annual respondents. Recent months are preliminary and subject to revision. Missing rows do not prove zero shipments.

Imported releases start 2008-01. This window includes 12 published months. EIA releases · Survey instructions

  • 2026 · preliminary · EIA923_Schedules_2_3_4_5_M_07_2026_21SEP2026.xlsx · Page 5 Fuel Receipts and Costs
  • 2025 · final · EIA923_Schedules_2_3_4_5_M_12_2025_Final.xlsx · Page 5 Fuel Receipts and Costs

Latest priced year: 2024Source checked 2026-10-13. Prices apply only to their calendar year.

FOB PRICE BENCHMARK · USD/TON—Published county average
ESTIMATED SALES · SHORT TONS—Allocated from published county sales
ESTIMATED COAL REVENUE · USD—Covered mines only · not reported revenue
ANNUAL PRODUCTION COVERED—0 of 0 producing annual mine records
Mine / countyAnnual production · tonsCounty FOB · USD/tonEst. sales · tonsEst. coal revenue · USDBasis / availability
Decker Mine2400839 · Location unavailable————No matching annual production record
Method, assumptions and source records
  1. This is an annual county-sales allocation, not reported mine or company revenue. Currency is nominal USD in the source year; quantities are short tons.
  2. Mine share = same-year annual mine production / eligible same-county production. Estimated sales = published county sales × share. Estimated coal revenue = estimated sales × published county average FOB price.
  3. The model assumes eligible mines share county sales in proportion to production and receive the county-average price. Matching mine counts is a check, not proof of identical respondents. Mine quality, contracts and sales timing can differ substantially. No statistical confidence interval is implied.
  4. FOB excludes transport and insurance. EIA-923 delivered costs do not enter this model. No grade premium, state/national fallback, quarterly apportionment or carry-forward to a later year is applied.
  5. Eligibility follows the source's production threshold and excludes preparation-only and refuse operations. Withheld values, inconsistent county counts and missing/ambiguous locations produce no estimate.
  6. County sales are published in thousands of tons and prices to cents. Calculations retain precision, but the inputs are rounded and the allocation is approximate.
  7. Portfolio attribution uses current MSHA ownership, not ownership during the sales year. Covered-mine sums exclude unavailable estimates and must not be read as whole-company revenue. Coverage denominators use the annual EIA mine-production release.

Sales-reporting threshold: 50,000 short tons per mine in 2024. Withheld sales or prices stay unavailable.

EIA Table 30 · county sales and FOB prices · EIA annual mine production · Release index

Annual report released November 19, 2025. Method: county-sales-allocation-v1. JSON and CSV preserve source row numbers and file checksums.

OWNERSHIP

Operator and controller history

Current ownership comes from MSHA Mines. Historical start and end dates come from MSHA Controller and Operator History.

CURRENT HIERARCHYLighthouse Resources Inc → Decker Coal Company → Decker Mine
HISTORY RECORDS48 relationships
INTERVAL CHECKPASScontroller/operator overlap
—

Lighthouse Resources InccontrolsDecker Coal CompanyoperatesDecker Mine

msha-controller-operator-history · controller/operator co-tenure derived on mine 2400839
—

Ambre Energy LimitedcontrolsDecker Coal CompanyoperatesDecker Mine

msha-controller-operator-history · controller/operator co-tenure derived on mine 2400839
—

Ambre Energy Limited et alcontrolsDecker Coal CompanyoperatesDecker Mine

msha-controller-operator-history · controller/operator co-tenure derived on mine 2400839
—

Cloud Peak Energy et alcontrolsDecker Coal CompanyoperatesDecker Mine

msha-controller-operator-history · controller/operator co-tenure derived on mine 2400839
Other historical summaries · source-specific periods

RECORD SUMMARY

Production, safety and enforcement

These summaries use the periods stated on each card, independently of the reporting period above.

01 / SAFETYwatch

Accidents and injuries

91 historical accident/injury rows; 0 coded fatalities and 2,566 lost days across the published record.

ACCIDENT + INJURY RECORD4 since 2021
accidentsmine-production-quarterly
02 / COMPLIANCEwatch

Violations and penalties

389 violation rows across the full record; 76 carry an S&S flag and $237,695 appears in current assessed amounts.

ENFORCEMENT ACTIVITY27 since 2021
inspectionsviolationsassessed-violationsorders-107a
03 / HEALTHwatch

Occupational health samples

480 coal dust; 27 coal quartz; 203 noise. 0 personal-sample rows have a published C/E ratio above 1; 31 noise rows have an action-level or PEL dose above 100%. These are separate measures, not a silica exceedance count. Silica results and sample status are shown separately.

OCCUPATIONAL EXPOSURE710 samples
coal-dust-samplesquartz-samplesnoise-samples
04 / PRODUCTIONcontext

Quarterly production and employment

11K employee hours and 21 summed average employees across reported subunits in the latest published quarter.

2026-Q20 tons
mine-production-quarterlymine-production-yearly
05 / LEGALwatch

Contests, conferences and decisions

25 contested-violation rows, 25 civil-penalty docket/decision rows, and 18 conference records linked by issuance number.

POST-ISSUANCE LIFECYCLE68 linked rows
conferencescontested-violationscivil-penalty-dockets-decisions
06 / CONTRACTORScontext

Contractors

Contractors are linked through this mine’s violation or accident records. Their production and hours cover all their operations, so they are not included in this mine’s totals.

ENTITY-LEVEL CONTEXT16 linked entities
contractor-production-quarterlycontractor-production-yearlyaccidentsviolations
07 / INSPECTIONScontext

Inspections

126 inspection events and 6K published inspection hours across the historical record.

OVERSIGHT COVERAGE16 since 2021
inspectionsviolations

HEALTH SAMPLING

Silica and quartz

Matching records11 coal · 0 personal · 0 area
Sample status1 not voided0 voided · 0 status not reported
Mean coal quartz concentration27 µg/m³1 eligible measurements · 0 missing concentration
2026 · Sep 2, 2026–Sep 2, 2026
Date / sampleDataset / analyteOccupation / areaMeasurementSample statusPublished action
58000804 / lab 2026036771Coal quartzQuartzBULLDOZER OPERATORDESIGNATED WORK POSITION27 µg/m³12% quartzNot voidedNot reported
Sources and interpretation
  • Coal means use numeric concentrations from samples marked not voided, excluding control/invalid sample types and dates after the snapshot. Missing values remain null; reported zeroes remain zero.
  • Quarterly means describe available samples, not mine-wide or worker-average exposure. Quarters with no eligible measurements remain empty; the current quarter is partial.
  • Personal C/E is MSHA's published concentration-to-limit ratio. A value above 1 is not by itself a citation or a determination under the 2024 silica rule. Personal and area files do not publish a void-status field.
  • Area records include bulk-dust analyses and are kept separate from personal exposure results. Their concentration units are not specified in the source dictionary.
  • Missing samples do not establish safe conditions. Coal quartz percentage and concentration are separate measures. No compliance threshold is inferred for coal samples.

Coal quartz field definitions ↗Metal/nonmetal personal field definitions ↗Metal/nonmetal area field definitions ↗

EIA + TITLE 30

EIA production and cited regulations

EIA annual figures are reported separately from MSHA. Regulation links use the current eCFR snapshot.

RECENT PUBLIC RECORDS

Recent violations and samples

Latest records retained for inspection; aggregates above use the full source history.

VIOLATIONS12 latest shown
960709677.1103(a)Citation
960709577.1110Citation
973302577.704-8(a)(1)Citation
973302477.1110Citation
503887747.41(a)Citation
973225577.1607(p)Citation
973225477.502Citation
973195077.502-2Citation
OTHER HEALTH SAMPLES8 latest shown

Coal dust, noise and other contaminants. Silica records above ↑

Coal dustBULLDOZER OPERATOR
.012 mg/m³Not voided
Coal dustBULLDOZER OPERATOR
.231 mg/m³Not voided
NoiseBULLDOZER OPERATOR
PEL dose: 75%Action-level dose: 122%
NoiseBULLDOZER OPERATOR
PEL dose: 54%Action-level dose: 71%
Coal dustBULLDOZER OPERATOR
.034 mg/m³Not voided
Coal dustBULLDOZER OPERATOR
.07 mg/m³Not voided
Coal dustBULLDOZER OPERATOR
.039 mg/m³Not voided
Coal dustBULLDOZER OPERATOR
.033 mg/m³Not voided

SOURCE COVERAGE

Reporting dates and coverage

17 datasets contain linked records. Missing datasets are listed below.

DATASETROWSWINDOWSTATUS
Accident, Injuries, and Illnessessafety · contractors91Jan 5, 2000—Feb 2, 2026mine-keyed
Addresses of Recordidentity · logistics1Sep 1, 1972—Sep 1, 1972mine-keyed
Assessed Violationscompliance · legal387Sep 25, 2000—Aug 27, 2026mine-keyed
Civil Penalty Dockets and Decisionscompliance · legal25Sep 30, 2010—Oct 22, 2019mine-keyed
Coal Dust Sampleshealth · safety480Jan 19, 2000—Sep 2, 2026mine-keyed
Conferencescompliance · legal18Nov 13, 2012—Oct 31, 2019mine-keyed
Contested Violationscompliance · legal25Jun 17, 2009—Apr 19, 2019mine-keyed
Contractor Employment and Production — Quarterlycontractors · production · safety2,579Not published—Not publishedentity-linked
Contractor Employment and Production — Yearlycontractors · production · safety498Not published—Not publishedentity-linked
Controller and Operator Historyidentity · compliance4Jan 1, 1950—Jan 1, 1950mine-keyed
Mine Employment and Production — Quarterlyproduction · safety · compliance307Not published—Not publishedmine-keyed
Mine Employment and Production — Yearlyproduction · safety · compliance75Not published—Not publishedmine-keyed
Inspectionssafety · compliance126Jan 19, 2000—Aug 24, 2026mine-keyed
Minesidentity · production · logistics1Not published—Not publishedmine-keyed
Metal and Nonmetal Area Sampleshealth · safety—No published rowsabsent / not applicable
Metal and Nonmetal Personal Health Sampleshealth · safety—No published rowsabsent / not applicable
Noise Sampleshealth · safety · equipment203May 23, 2000—Sep 2, 2026mine-keyed
Quartz Samples — Coalhealth · safety27Jan 19, 2000—Sep 2, 2026mine-keyed
Violationscompliance · safety · legal389Sep 25, 2000—Aug 27, 2026mine-keyed
107(a) Orders Issuedsafety · compliance—No published rowsabsent / not applicable

NOTES

Limitations

  • Contractor production is entity-level and is never represented as mine-attributable.
  • Missing rows can mean no event, publication delay, identity mismatch, or inapplicability.