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

MINE DETAILS

Portable #1

Temporarily IdledSurfaceConstruction Sand and Gravel
MSHA MINE ID4801636
LOCATIONBig Horn, WY
PUBLIC RECORD432 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

9

1 significant & substantial (S&S)

  1. 2025 Q12
  2. 2025 Q20
  3. 2025 Q34
  4. 2025 Q40
  5. 2026 Q13
  6. 2026 Q20
  7. 2026 Q30
  8. 2026 Q4 *0

Accident records

0

0 records classified as fatality

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

Proposed penalties · USD

1,606.00

9 of 9 violations with amounts

  1. 2025 Q1302
  2. 2025 Q2—
  3. 2025 Q3604
  4. 2025 Q4—
  5. 2026 Q1700
  6. 2026 Q2—
  7. 2026 Q3—
  8. 2026 Q4 *—

On-site inspection hours

16.50

3 inspections · 3 with hours

  1. 2025 Q15.25
  2. 2025 Q2—
  3. 2025 Q36.50
  4. 2025 Q4—
  5. 2026 Q14.75
  6. 2026 Q2—
  7. 2026 Q3—
  8. 2026 Q4 *—
Quarterly safety data
QuarterViolationsS&SProposed USDAccident recordsFatality recordsInspectionsOn-site hours
2025-Q120302.000015.3
2025-Q200—000—
2025-Q340604.000016.5
2025-Q400—000—
2026-Q131700.000014.8
2026-Q200—000—
2026-Q300—000—
2026-Q4 *00—000—

Most cited CFR sections

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

Safety activity

  1. inspectionF03AB0B

    Regular Safety and Health Inspection · 4.8 on-site hours

  2. violation5038907

    56.12032 · S&S · $398.00 proposed

  3. violation5038906

    56.12028 · $151.00 proposed

  4. violation5038905

    56.12030 · $151.00 proposed

  5. inspection6469043

    Regular Safety and Health Inspection · 6.5 on-site hours

  6. violation9731186

    56.14132(a) · $151.00 proposed

  7. violation9731185

    56.14100(b) · $151.00 proposed

  8. violation9731184

    56.12030 · $151.00 proposed

  9. violation9731183

    56.14100(b) · $151.00 proposed

  10. violation9909655

    56.12025 · $151.00 proposed

  11. violation9909654

    56.14107(a) · $151.00 proposed

  12. inspectionF00258D

    Regular Safety and Health Inspection · 5.3 on-site hours

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.

OWNERSHIP

Operator and controller history

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

CURRENT HIERARCHYD Michael Frost → Mountain Construction Company → Portable #1
HISTORY RECORDS13 relationships
INTERVAL CHECKPASScontroller/operator overlap
—

D Michael FrostcontrolsMountain Construction CompanyoperatesPortable #1

msha-controller-operator-history · controller/operator co-tenure derived on mine 4801636
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

2 historical accident/injury rows; 0 coded fatalities and 70 lost days across the published record.

ACCIDENT + INJURY RECORD1 since 2021
accidentsmine-production-quarterly
02 / COMPLIANCEwatch

Violations and penalties

91 violation rows across the full record; 29 carry an S&S flag and $34,091 appears in current assessed amounts.

ENFORCEMENT ACTIVITY41 since 2021
inspectionsviolationsassessed-violationsorders-107a
03 / HEALTHcontext

Occupational health samples

17 personal. 0 personal-sample rows have a published C/E ratio above 1; 0 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 EXPOSURE17 samples
personal-health-samples
04 / PRODUCTIONcontext

Quarterly production and employment

2K employee hours and 12 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

0 contested-violation rows, 3 civil-penalty docket/decision rows, and 4 conference records linked by issuance number.

POST-ISSUANCE LIFECYCLE7 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 CONTEXT1 linked entities
contractor-production-quarterlycontractor-production-yearlyaccidentsviolations
07 / INSPECTIONScontext

Inspections

39 inspection events and 560 published inspection hours across the historical record.

OVERSIGHT COVERAGE14 since 2021
inspectionsviolations

HEALTH SAMPLING

Silica and quartz

Matching records00 coal · 0 personal · 0 area
Sample status0 not voided0 voided · 0 status not reported
Personal samples with C/E > 1—0 published ratios · not a citation count
2026 · No reported dates in this selection
Date / sampleDataset / analyteOccupation / areaMeasurementSample statusPublished action
No silica records match these filters. Missing samples do not establish safe conditions.
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
503890756.12032S&S
503890656.12028Citation
503890556.12030Citation
973118656.14132(a)Citation
973118556.14100(b)Citation
973118456.12030Citation
973118356.14100(b)Citation
990965556.12025Citation
OTHER HEALTH SAMPLES6 latest shown

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

Respirable dust, <.1mgFront-end Loader Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgFront-end Loader Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgCrusher Oper/Worker
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgCrusher Oper/Worker
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgCrusher Oper/Worker
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgFront-end Loader Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified

SOURCE COVERAGE

Reporting dates and coverage

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

DATASETROWSWINDOWSTATUS
Accident, Injuries, and Illnessessafety · contractors2Jan 22, 2020—Apr 7, 2022mine-keyed
Addresses of Recordidentity · logistics1May 13, 2026—May 13, 2026mine-keyed
Assessed Violationscompliance · legal91Jul 29, 2003—Jan 6, 2026mine-keyed
Civil Penalty Dockets and Decisionscompliance · legal3Aug 31, 2004—Aug 31, 2004mine-keyed
Coal Dust Sampleshealth · safety—No published rowsabsent / not applicable
Conferencescompliance · legal4Feb 16, 2004—Feb 16, 2004mine-keyed
Contested Violationscompliance · legal—No published rowsabsent / not applicable
Contractor Employment and Production — Quarterlycontractors · production · safety6Not published—Not publishedentity-linked
Contractor Employment and Production — Yearlycontractors · production · safety—No published rowsabsent / not applicable
Controller and Operator Historyidentity · compliance1Feb 18, 2003—Feb 18, 2003mine-keyed
Mine Employment and Production — Quarterlyproduction · safety · compliance144Not published—Not publishedmine-keyed
Mine Employment and Production — Yearlyproduction · safety · compliance32Not published—Not publishedmine-keyed
Inspectionssafety · compliance39Jul 29, 2003—Jan 6, 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 · safety17Aug 4, 2009—Mar 12, 2024mine-keyed
Noise Sampleshealth · safety · equipment—No published rowsabsent / not applicable
Quartz Samples — Coalhealth · safety—No published rowsabsent / not applicable
Violationscompliance · safety · legal91Jul 29, 2003—Jan 6, 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.