MINE DETAILS
Black Mountain Quarry
MSHA MINE ID0405701
LOCATION
Mine location
1 of 1 mine with usable MSHA coordinates. Select a marker to open a mine.
Mine coordinates
- Black Mountain Quarry34.61694, -117.12806Open map ↗
Quarterly trends
2025 Q1 – 2026 Q4
Database snapshot · 2026-10-18. MSHA quarterly production and employment reports.
Coal production
0reported short tons
Hours worked
599,804reported 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 | 110,391 | 0.00 | 180 | 1/1 mines reporting |
| 2025 Q2 | 0 | 95,099 | 0.00 | 158 | 1/1 mines reporting |
| 2025 Q3 | 0 | 91,438 | 0.00 | 152 | 1/1 mines reporting |
| 2025 Q4 | 0 | 92,882 | 0.00 | 154 | 1/1 mines reporting |
| 2026 Q1 | 0 | 100,196 | 0.00 | 175 | 1/1 mines reporting |
| 2026 Q2 | 0 | 109,798 | 0.00 | 182 | 1/1 mines reporting |
| 2026 Q3 | — | — | — | — | No report |
| 2026 Q4 | — | — | — | — | No report |
Safety and enforcement
2025-01-01 – 2026-10-18
Violations
11034 significant & substantial (S&S)
Accident records
80 records classified as fatality
Proposed penalties · USD
79,700.00110 of 110 violations with amounts
On-site inspection hours
366.008 inspections · 8 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 | 0 | 0 | — | 1 | 0 | 0 | — |
| 2025-Q2 | 27 | 8 | 18,850.00 | 2 | 0 | 1 | 105.0 |
| 2025-Q3 | 1 | 0 | 151.00 | 1 | 0 | 0 | — |
| 2025-Q4 | 32 | 11 | 25,858.00 | 0 | 0 | 2 | 100.5 |
| 2026-Q1 | 30 | 11 | 22,257.00 | 4 | 0 | 4 | 156.0 |
| 2026-Q2 | 20 | 4 | 12,584.00 | 0 | 0 | 0 | — |
| 2026-Q3 | 0 | 0 | — | 0 | 0 | 1 | 4.5 |
| 2026-Q4 * | 0 | 0 | — | 0 | 0 | 0 | — |
Most cited CFR sections
All violations issued in the selected period. Counts combine subsections.
Safety activity
56.4200(b)(2) · $151.00 proposed
EXPLODING VESSELS UNDER PRESSURE · DAYS RESTRICTED ACTIVITY ONLY
Accident narrative
The employee responded to a high-temperature alarm on the impactor crushers displayed on the HMI. As part of normal correction, the employee proceeded to the impactor building to activate the air horns for each impactor unit. The employee then proceeded to BIC2 and opened the air horn valve. A loose hose end became pressurized and struck the employee in the left eye.
Verbal Hazard Complaint Inspections · 2.0 on-site hours
HANDLING OF MATERIALS · DAYS RESTRICTED ACTIVITY ONLY
Accident narrative
EE was lifting a full oxygen bottle into a UTV and during this task the bottle slipped pinching their right ring finger in between the bottle and tailgate causing a laceration and fracture of the finger.
ENTRAPMENT · ACCIDENT ONLY
Accident narrative
K2 Elevator stopped between 6&7 floor w/ contractor inside @ 13:24. MSHA called 13:55 ref. 04940914. Service contractor notified & arrived 15:25. Stuck person out at 16:03. MSHA notified 16:04.
56.14205 · $818.00 proposed
Spot Inspection · 4.5 on-site hours
ENTRAPMENT · ACCIDENT ONLY
Accident narrative
K2 elevator stopped moving with contractor inside. Contacted Control Room approx 12:25pm. Attempts to get elevator to move unsuccessful. Contracted elevator service company called. MSHA notified of entrapment approx 12:55pm. Elevator service contractor tech arrived. Stuck person out approx 1:50pm. Contactor wheel was replaced. MSHA notified that person got out at approx 2:00pm
Verbal Hazard Complaint Inspections · 3.5 on-site hours
Verbal Hazard Complaint Inspections · 2.8 on-site hours
56.4402 · $151.00 proposed
56.18002(a) · S&S · $366.00 proposed
56.16001 · $151.00 proposed
56.12023 · S&S · $151.00 proposed
56.20003(a) · S&S · $151.00 proposed
56.16001 · $151.00 proposed
56.14103(b) · $151.00 proposed
46.6(a) · $610.00 proposed
45.4(a) · $151.00 proposed
56.12008 · $151.00 proposed
56.4011 · $151.00 proposed
56.15001 · $151.00 proposed
56.16001 · $151.00 proposed
56.20003(a) · S&S · $366.00 proposed
56.9300(d) · $366.00 proposed
Safety sources and definitions
MSHA Violations (issue date), Accidents (accident date), and Inspections (begin date). Snapshot 2026-10-18.
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.
—
Cemex S AcontrolsCEMEX Construction Materials Pacific, LLCoperatesBlack Mountain Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 0405701—
Cemex S AcontrolsCemex California Cement LLCoperatesBlack Mountain Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 0405701Other 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
167 historical accident/injury rows; 0 coded fatalities and 1,516 lost days across the published record.
ACCIDENT + INJURY RECORD24 since 2021
accidentsmine-production-quarterly02 / COMPLIANCEwatch
Violations and penalties
1,553 violation rows across the full record; 435 carry an S&S flag and $1,649,322 appears in current assessed amounts.
ENFORCEMENT ACTIVITY442 since 2021
inspectionsviolationsassessed-violationsorders-107a03 / HEALTHwatch
Occupational health samples
85 personal. 11 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 EXPOSURE85 samples
personal-health-samples04 / PRODUCTIONcontext
Quarterly production and employment
110K employee hours and 182 summed average employees across reported subunits in the latest published quarter.
2026-Q20 tons
mine-production-quarterlymine-production-yearly05 / LEGALwatch
Contests, conferences and decisions
348 contested-violation rows, 348 civil-penalty docket/decision rows, and 21 conference records linked by issuance number.
POST-ISSUANCE LIFECYCLE717 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 CONTEXT56 linked entities
contractor-production-quarterlycontractor-production-yearlyaccidentsviolations07 / INSPECTIONScontext
Inspections
195 inspection events and 9K published inspection hours across the historical record.
OVERSIGHT COVERAGE34 since 2021
inspectionsviolationsHEALTH SAMPLING
Silica and quartz
Coal quartz, metal/nonmetal personal samples and area samples. Snapshot Oct 18, 2026. 7 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 |
|---|---|---|---|---|---|
| 000000202601442300 | Metal/nonmetal personalQuartz, respirable, >1% Qtz | Cleanup Man | 0.28× published limitConcentration: 0000.69 · limit: 0002.44Source unit unspecified | Not reported | NO ACTIONInspection F017884 |
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 56.12004Electrical conductors.1 recent row ↗30 CFR 56.14100Safety defects; examination, correction and records.1 recent row ↗30 CFR 56.4200General requirements.1 recent row ↗30 CFR 56.4011Abandoned electric circuits.1 recent row ↗30 CFR 56.14107Moving machine parts.2 recent rows ↗30 CFR 56.14207Parking procedures for unattended equipment.1 recent row ↗30 CFR 46.11Site-specific hazard awareness training.1 recent row ↗30 CFR 46.9Records of training.1 recent row ↗
RECENT PUBLIC RECORDS
Recent violations and samples
Latest records retained for inspection; aggregates above use the full source history.
516663456.12004Citation
516625556.14100(a)Citation
516625456.4200(b)(2)Citation
516625356.4011Citation
516663356.14107Citation
516663256.14207S&S
516663146.11(b)(3)S&S
516526846.9(b)(5)Citation
Coal dust, noise and other contaminants. Silica records above ↑
Respirable dust, <.1mgUtility Man
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgYard Engine Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgYard Engine Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Nuisance dust, respirable, <1% QtzBobcat Operator
C/E: 00.03Concentration: 0000.32 · limit: 0010.00Source unit unspecified
Respirable dust, <.1mgBuilding Repair/Maint.
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Nuisance dust, respirable, <1% QtzMechanic
C/E: 00.06Concentration: 0000.58 · limit: 0010.00Source unit unspecified
SOURCE COVERAGE
Reporting dates and coverage
15 datasets contain linked records. Missing datasets are listed below.
DATASETROWSWINDOWSTATUS
Accident, Injuries, and Illnessessafety · contractors167Jan 5, 2007—Mar 17, 2026mine-keyed
Addresses of Recordidentity · logistics1Dec 29, 2006—Dec 29, 2006mine-keyed
Assessed Violationscompliance · legal1,535Jan 30, 2007—Apr 8, 2026mine-keyed
Civil Penalty Dockets and Decisionscompliance · legal348Aug 7, 2009—Jun 12, 2026mine-keyed
Coal Dust Sampleshealth · safety—No published rowsabsent / not applicable
Conferencescompliance · legal21Mar 26, 2007—Jun 1, 2026mine-keyed
Contested Violationscompliance · legal348Apr 30, 2007—Apr 8, 2026mine-keyed
Contractor Employment and Production — Quarterlycontractors · production · safety6,349Not published—Not publishedentity-linked
Contractor Employment and Production — Yearlycontractors · production · safety1,504Not published—Not publishedentity-linked
Controller and Operator Historyidentity · compliance2Jan 1, 2007—Jan 1, 2010mine-keyed
Mine Employment and Production — Quarterlyproduction · safety · compliance234Not published—Not publishedmine-keyed
Mine Employment and Production — Yearlyproduction · safety · compliance60Not published—Not publishedmine-keyed
Inspectionssafety · compliance195Jan 23, 2007—Jul 30, 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 · safety85Jul 18, 2007—Apr 9, 2026mine-keyed
Noise Sampleshealth · safety · equipment—No published rowsabsent / not applicable
Quartz Samples — Coalhealth · safety—No published rowsabsent / not applicable
Violationscompliance · safety · legal1,553Jan 30, 2007—Apr 8, 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.