MINE DETAILS
Bonanza Mines
MSHA MINE ID4200854
LOCATION
Mine location
1 of 1 mine with usable MSHA coordinates. Select a marker to open a mine.
Mine coordinates
- Bonanza Mines40.01944, -109.17667Open map ↗
Quarterly trends
2025 Q1 – 2026 Q4
Database snapshot · 2026-10-13. MSHA quarterly production and employment reports.
Coal production
0reported short tons
Hours worked
146,040reported employee hours
Tons per hour
0.00production ÷ hours worked
Missing values appear as —. Totals use available reports. Tons per hour requires production and hours for the same quarters and a nonzero hours total. * Striped bars mark partial mine coverage or an incomplete quarter. See the table for coverage.
Quarterly data and reporting coverage
| Quarter | Coal (short tons) | Hours worked | Tons / hour | Avg. employees | Coverage |
|---|---|---|---|---|---|
| 2025 Q1 | 0 | 28,113 | 0.00 | 38 | 1/1 mines reporting |
| 2025 Q2 | 0 | 27,980 | 0.00 | 49 | 1/1 mines reporting |
| 2025 Q3 | 0 | 19,008 | 0.00 | 37 | 1/1 mines reporting |
| 2025 Q4 | 0 | 22,540 | 0.00 | 37 | 1/1 mines reporting |
| 2026 Q1 | 0 | 20,266 | 0.00 | 42 | 1/1 mines reporting |
| 2026 Q2 | 0 | 28,133 | 0.00 | 41 | 1/1 mines reporting |
| 2026 Q3 | — | — | — | — | No report |
| 2026 Q4 | — | — | — | — | No report |
Safety and enforcement
2025-01-01 – 2026-10-13
Violations
173 significant & substantial (S&S)
Accident records
30 records classified as fatality
Proposed penalties · USD
3,356.0017 of 17 violations with amounts
On-site inspection hours
370.759 inspections · 9 with hours
Counts are published records, including contractor records. * The quarter was incomplete at the snapshot date; recent counts may rise as reports arrive. — means no reported amount or hours. Portfolio totals use current membership.
Quarterly safety data
| Quarter | Violations | S&S | Proposed USD | Accident records | Fatality records | Inspections | On-site hours |
|---|---|---|---|---|---|---|---|
| 2025-Q1 | 5 | 2 | 1,544.00 | 1 | 0 | 2 | 37.5 |
| 2025-Q2 | 5 | 0 | 755.00 | 0 | 0 | 1 | 82.3 |
| 2025-Q3 | 2 | 0 | 302.00 | 0 | 0 | 2 | 30.0 |
| 2025-Q4 | 1 | 0 | 151.00 | 0 | 0 | 1 | 69.0 |
| 2026-Q1 | 3 | 1 | 453.00 | 1 | 0 | 1 | 52.5 |
| 2026-Q2 | 1 | 0 | 151.00 | 0 | 0 | 1 | 49.0 |
| 2026-Q3 | 0 | 0 | — | 1 | 0 | 1 | 50.5 |
| 2026-Q4 * | 0 | 0 | — | 0 | 0 | 0 | — |
Most cited CFR sections
All violations issued in the selected period. Counts combine subsections.
Safety activity
Regular Safety and Health Inspection · 50.5 on-site hours
HANDTOOLS (NONPOWERED) · DAYS AWAY FROM WORK ONLY
Accident narrative
A miner was using a hammer to nail in 2-inch shaft boards. The miner felt a pop in their shoulder while swinging the hammer. The next day, the miner's bicep was bruised and swollen.
57.4201(a)(1) · $151.00 proposed
Regular Safety and Health Inspection · 49.0 on-site hours
SLIP OR FALL OF PERSON · DAYS AWAY FROM WORK ONLY
Accident narrative
A miner was standing on a 3"x8"x12' board, mining ore. The board broke under the miner's weight, and the miner rolled their ankle. The ankle sustained a displacement fracture at the bottom of the tibia at the ankle.
57.4201(a)(1) · $151.00 proposed
57.12004 · S&S · $151.00 proposed
57.14100(b) · $151.00 proposed
Regular Safety and Health Inspection · 52.5 on-site hours
62.130(a) · $151.00 proposed
Regular Safety and Health Inspection · 69.0 on-site hours
Compliance Follow-up Inspection · 0.0 on-site hours
57.12028 · $151.00 proposed
56.4101 · $151.00 proposed
Regular Safety and Health Inspection · 30.0 on-site hours
56.12018 · $151.00 proposed
57.4201(a)(2) · $151.00 proposed
57.4201(a)(1) · $151.00 proposed
57.12025 · $151.00 proposed
57.12004 · $151.00 proposed
Regular Safety and Health Inspection · 82.3 on-site hours
Compliance Follow-up Inspection · 6.0 on-site hours
62.130(a) · $151.00 proposed
62.130(a) · $151.00 proposed
57.19109 · S&S · $755.00 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.
OWNERSHIP
Operator and controller history
Current ownership comes from MSHA Mines. Historical start and end dates come from MSHA Controller and Operator History.
—
American Gilsonite CompanycontrolsAmerican Gilsonite CompanyoperatesBonanza Mines
msha-controller-operator-history · controller/operator co-tenure derived on mine 4200854—
Chevron CorporationcontrolsAmerican Gilsonite CompanyoperatesBonanza Mines
msha-controller-operator-history · controller/operator co-tenure derived on mine 4200854—
R E NelsoncontrolsAmerican Gilsonite CompanyoperatesBonanza Mines
msha-controller-operator-history · controller/operator co-tenure derived on mine 4200854Other 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
160 historical accident/injury rows; 0 coded fatalities and 2,603 lost days across the published record.
ACCIDENT + INJURY RECORD16 since 2021
accidentsmine-production-quarterly02 / COMPLIANCEwatch
Violations and penalties
501 violation rows across the full record; 100 carry an S&S flag and $128,082 appears in current assessed amounts.
ENFORCEMENT ACTIVITY65 since 2021
inspectionsviolationsassessed-violationsorders-107a03 / HEALTHcontext
Occupational health samples
129 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 EXPOSURE129 samples
personal-health-samples04 / PRODUCTIONcontext
Quarterly production and employment
28K employee hours and 41 summed average employees across reported subunits in the latest published quarter.
2026-Q20 tons
mine-production-quarterlymine-production-yearly05 / LEGALwatch
Contests, conferences and decisions
10 contested-violation rows, 12 civil-penalty docket/decision rows, and 1 conference records linked by issuance number.
POST-ISSUANCE LIFECYCLE23 linked rows
conferencescontested-violationscivil-penalty-dockets-decisions06 / 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 CONTEXT8 linked entities
contractor-production-quarterlycontractor-production-yearlyaccidentsviolations07 / INSPECTIONScontext
Inspections
163 inspection events and 12K published inspection hours across the historical record.
OVERSIGHT COVERAGE27 since 2021
inspectionsviolationsHEALTH SAMPLING
Silica and quartz
Coal quartz, metal/nonmetal personal samples and area samples. Snapshot Oct 13, 2026. 15 silica records across the mine’s published history.
Personal silica samples · concentration / limit
Quarterly mean · published C/E ratio
— No eligible measurements. * Quarter in progress. Means describe the available samples, not average exposure across the mine.
Quartz % is the sample’s quartz content; µg/m³ is its reported concentration. Personal C/E is the ratio to the limit published with that sample. Personal and area concentration units and void status are not specified in those source files.
| Date / sample | Dataset / analyte | Occupation / area | Measurement | Sample status | Published action |
|---|---|---|---|---|---|
| 000000202603618000 | Metal/nonmetal personalQuartz, respirable, >1% Qtz | Miner, Stope | 0× published limitConcentration: 0000.24 · limit: 0000.00Source unit unspecified | Not reported | NO ACTIONInspection F00E3E5 |
| 000000202603618100 | Metal/nonmetal personalQuartz, respirable, >1% Qtz | Miner, Stope | 0× published limitConcentration: 0000.22 · limit: 0000.00Source unit unspecified | Not reported | NO ACTIONInspection F00E3E5 |
| 000000202600110300 | Metal/nonmetal personalQuartz, respirable, >1% Qtz | Miner, Drift | 0× published limitConcentration: 0000.35 · limit: 0000.00Source unit unspecified | Not reported | NO ACTIONInspection F022E5C |
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.
Not present in the 2024 EIA coal workbook.
This can mean the operation is non-coal, inactive for the annual period, or outside the EIA-7A reporting population.
30 CFR 57.4201Inspection.4 recent rows ↗30 CFR 57.12004Electrical conductors.2 recent rows ↗30 CFR 57.14100Safety defects; examination, correction and records.1 recent row ↗30 CFR 62.130Permissible exposure level.1 recent row ↗30 CFR 57.12028Testing grounding systems.1 recent row ↗30 CFR 56.4101Warning signs.1 recent row ↗30 CFR 56.12018Identification of power switches.1 recent row ↗30 CFR 57.12025Grounding circuit enclosures.1 recent row ↗
RECENT PUBLIC RECORDS
Recent violations and samples
Latest records retained for inspection; aggregates above use the full source history.
503093557.4201(a)(1)Citation
973371157.4201(a)(1)Citation
973371057.12004S&S
503089057.14100(b)Citation
503906762.130(a)Citation
503084657.12028Citation
503048656.4101Citation
503043856.12018Citation
Coal dust, noise and other contaminants. Silica records above ↑
Nuisance dust, respirable, <1% QtzHoist Operator
C/E: 00.04Concentration: 0000.38 · limit: 0010.00Source unit unspecified
Respirable dust, <.1mgMiner, Drift
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Nuisance dust, respirable, <1% QtzMiner, Drift
C/E: 00.18Concentration: 0001.77 · limit: 0010.00Source unit unspecified
Respirable dust, <.1mgHoist Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgHoist Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgMiner, Drift
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
SOURCE COVERAGE
Reporting dates and coverage
15 datasets contain linked records. Missing datasets are listed below.
DATASETROWSWINDOWSTATUS
Accident, Injuries, and Illnessessafety · contractors160Jan 19, 2000—Aug 17, 2026mine-keyed
Addresses of Recordidentity · logistics1Jun 22, 1982—Jun 22, 1982mine-keyed
Assessed Violationscompliance · legal492Mar 7, 2000—Jun 24, 2026mine-keyed
Civil Penalty Dockets and Decisionscompliance · legal12Feb 10, 2003—Sep 13, 2023mine-keyed
Coal Dust Sampleshealth · safety—No published rowsabsent / not applicable
Conferencescompliance · legal1Feb 12, 2001—Feb 12, 2001mine-keyed
Contested Violationscompliance · legal10Jun 28, 2007—Apr 13, 2023mine-keyed
Contractor Employment and Production — Quarterlycontractors · production · safety1,214Not published—Not publishedentity-linked
Contractor Employment and Production — Yearlycontractors · production · safety293Not published—Not publishedentity-linked
Controller and Operator Historyidentity · compliance3Jan 1, 1981—Aug 1, 1991mine-keyed
Mine Employment and Production — Quarterlyproduction · safety · compliance399Not published—Not publishedmine-keyed
Mine Employment and Production — Yearlyproduction · safety · compliance99Not published—Not publishedmine-keyed
Inspectionssafety · compliance163Mar 7, 2000—Sep 1, 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 · safety129Feb 17, 2010—Sep 2, 2026mine-keyed
Noise Sampleshealth · safety · equipment—No published rowsabsent / not applicable
Quartz Samples — Coalhealth · safety—No published rowsabsent / not applicable
Violationscompliance · safety · legal501Mar 7, 2000—Jun 24, 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.