MINE DETAILS
Thornton Quarry
MSHA MINE ID1100066
LOCATION
Mine location
1 of 1 mine with usable MSHA coordinates. Select a marker to open a mine.
Mine coordinates
- Thornton Quarry41.56583, -87.61361Open 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
223,776reported 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 | 24,761 | 0.00 | 41 | 1/1 mines reporting |
| 2025 Q2 | 0 | 45,336 | 0.00 | 59 | 1/1 mines reporting |
| 2025 Q3 | 0 | 45,313 | 0.00 | 60 | 1/1 mines reporting |
| 2025 Q4 | 0 | 38,586 | 0.00 | 58 | 1/1 mines reporting |
| 2026 Q1 | 0 | 25,670 | 0.00 | 43 | 1/1 mines reporting |
| 2026 Q2 | 0 | 44,110 | 0.00 | 60 | 1/1 mines reporting |
| 2026 Q3 | — | — | — | — | No report |
| 2026 Q4 | — | — | — | — | No report |
Safety and enforcement
2025-01-01 – 2026-10-13
Violations
80 significant & substantial (S&S)
Accident records
40 records classified as fatality
Proposed penalties · USD
2,718.008 of 8 violations with amounts
On-site inspection hours
209.757 inspections · 7 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 | 1 | 0 | 818.00 | 0 | 0 | 1 | 24.3 |
| 2025-Q2 | 0 | 0 | — | 1 | 0 | 0 | — |
| 2025-Q3 | 3 | 0 | 1,296.00 | 0 | 0 | 1 | 71.0 |
| 2025-Q4 | 0 | 0 | — | 1 | 0 | 1 | 13.0 |
| 2026-Q1 | 2 | 0 | 302.00 | 1 | 0 | 2 | 27.8 |
| 2026-Q2 | 2 | 0 | 302.00 | 1 | 0 | 1 | 64.3 |
| 2026-Q3 | 0 | 0 | — | 0 | 0 | 1 | 9.5 |
| 2026-Q4 * | 0 | 0 | — | 0 | 0 | 0 | — |
Most cited CFR sections
All violations issued in the selected period. Counts combine subsections.
Safety activity
Spot Inspection · 9.5 on-site hours
56.4200(b)(2) · $151.00 proposed
56.14132(a) · $151.00 proposed
Regular Safety and Health Inspection · 64.3 on-site hours
HANDLING OF MATERIALS · DAYS AWAY FROM WORK ONLY
Accident narrative
At the start of the shift employee was climbing access ladder of 992G FEL. Employee stated they felt right arm tingle and feel numb. They did not slip or try to catch themselves, was just climbing ladder normally. EE was taken to clinic, diagnosed w/ arm/shoulder strain, placed on restricted duty and referred to PT for eval and treatment
56.14100(b) · $151.00 proposed
56.11001 · $151.00 proposed
Regular Safety and Health Inspection · 25.0 on-site hours
Non-Chargeable Accident Investigation · 2.8 on-site hours
OTHER · INJURIES INVOLVNG NONEMPLOYEES
Accident narrative
Contact person was called by the Illinois Tollway on the afternoon of 1/27/26 about a missing person that was suicidal that may have jumped in the West Quarry off of the 80/94 tollway. Second contact was contacted around 4:00PM to come help search the West Quarry. At around 4:50PM the body of the trespasser was found and reported to authority's and the department of labor.
Non-Chargeable Accident Investigation · 13.0 on-site hours
SLIP OR FALL OF PERSON · INJURIES INVOLVNG NONEMPLOYEES
Accident narrative
Approx. 10:39pm on 11/22 we were contacted by Thornton fire dept. with a request for access to recover the body of an individual who had jumped to their death from Interstate 80/94 Tri-state tollway. The body was located approx. 150' below the road surface and was not accessible from the quarry & Was NOT Part of Mine Property according to Property Maps.
56.12004 · $288.00 proposed
56.12021 · $504.00 proposed
56.12068 · $504.00 proposed
Regular Safety and Health Inspection · 71.0 on-site hours
HANDLING OF MATERIALS · DAYS AWAY FROM WORK ONLY
Accident narrative
Employee was organizing parts in a storage area. EE had a shaker screen counterweight on the tines of a forklift. EE slid the counterweight off the tines of the forklift, when EE did EE felt a twinge in right shoulder. Self-treated until Monday, when EE was seen at a clinic, diagnosed with a muscle strain, placed on restricted duty (no use of R arm) until follow up appt.
Regular Safety and Health Inspection · 24.3 on-site hours
56.12068 · $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.
OWNERSHIP
Operator and controller history
Current ownership comes from MSHA Mines. Historical start and end dates come from MSHA Controller and Operator History.
—
Heidelberg Materials AGcontrolsHeidelberg Materials Midwest Agg, Inc.operatesThornton Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 1100066—
Hanson PLCcontrolsHeidelberg Materials Midwest Agg, Inc.operatesThornton Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 1100066—
Heidelberg Materials AGcontrolsHanson Material ServiceoperatesThornton Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 1100066—
Hanson PLCcontrolsHanson Material ServiceoperatesThornton Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 1100066—
General Dynamics CorpcontrolsHanson Material ServiceoperatesThornton Quarry
msha-controller-operator-history · controller/operator co-tenure derived on mine 1100066Other 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
85 historical accident/injury rows; 0 coded fatalities and 1,908 lost days across the published record.
ACCIDENT + INJURY RECORD13 since 2021
accidentsmine-production-quarterly02 / COMPLIANCEwatch
Violations and penalties
688 violation rows across the full record; 108 carry an S&S flag and $176,310 appears in current assessed amounts.
ENFORCEMENT ACTIVITY138 since 2021
inspectionsviolationsassessed-violationsorders-107a03 / HEALTHwatch
Occupational health samples
48 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 EXPOSURE48 samples
personal-health-samples04 / PRODUCTIONcontext
Quarterly production and employment
44K employee hours and 60 summed average employees across reported subunits in the latest published quarter.
2026-Q20 tons
mine-production-quarterlymine-production-yearly05 / LEGALwatch
Contests, conferences and decisions
78 contested-violation rows, 78 civil-penalty docket/decision rows, and 7 conference records linked by issuance number.
POST-ISSUANCE LIFECYCLE163 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 CONTEXT11 linked entities
contractor-production-quarterlycontractor-production-yearlyaccidentsviolations07 / INSPECTIONScontext
Inspections
112 inspection events and 5K published inspection hours across the historical record.
OVERSIGHT COVERAGE25 since 2021
inspectionsviolationsHEALTH SAMPLING
Silica and quartz
Coal quartz, metal/nonmetal personal samples and area samples. Snapshot Oct 13, 2026. 29 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 |
|---|---|---|---|---|---|
| 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.
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 56.4200General requirements.1 recent row ↗30 CFR 56.14132Horns and backup alarms.1 recent row ↗30 CFR 56.14100Safety defects; examination, correction and records.1 recent row ↗30 CFR 56.11001Safe access.1 recent row ↗30 CFR 56.12004Electrical conductors.1 recent row ↗30 CFR 56.12021Danger signs.1 recent row ↗30 CFR 56.12068Locking transformer enclosures.2 recent rows ↗30 CFR 56.4102Spillage and leakage.1 recent row ↗
RECENT PUBLIC RECORDS
Recent violations and samples
Latest records retained for inspection; aggregates above use the full source history.
978073856.4200(b)(2)Citation
501444256.14132(a)Citation
978887956.14100(b)Citation
978887856.11001Citation
655353756.12004Citation
655353656.12021Citation
655353556.12068Citation
962247756.12068Citation
Coal dust, noise and other contaminants. Silica records above ↑
Respirable dust, <.1mgBelt Crew
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Nuisance dust, respirable, <1% QtzScreen/Scalper Operator
C/E: 00.27Concentration: 0002.65 · limit: 0010.00Source unit unspecified
Respirable dust, <.1mgWasher Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Nuisance dust, total, <1% QtzHand Loader
C/E: 00.14Concentration: 0001.43 · limit: 0010.00Source unit unspecified
Nuisance dust, total, <1% QtzBall Mill Operator
C/E: 00.27Concentration: 0002.74 · limit: 0010.00Source unit unspecified
Nuisance dust, total, <1% QtzSkip Dumper, Toploader, Tipple Operator
C/E: 00.09Concentration: 0000.90 · limit: 0010.00Source unit unspecified
Nuisance dust, total, <1% QtzBall Mill Operator
C/E: 00.04Concentration: 0000.41 · 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 · contractors85Jan 20, 2001—Apr 6, 2026mine-keyed
Addresses of Recordidentity · logistics1Jun 25, 2013—Jun 25, 2013mine-keyed
Assessed Violationscompliance · legal688Oct 3, 2000—Jun 23, 2026mine-keyed
Civil Penalty Dockets and Decisionscompliance · legal78Oct 27, 2010—Jun 15, 2021mine-keyed
Coal Dust Sampleshealth · safety—No published rowsabsent / not applicable
Conferencescompliance · legal7Aug 21, 2012—Sep 8, 2017mine-keyed
Contested Violationscompliance · legal78Sep 1, 2009—Oct 8, 2020mine-keyed
Contractor Employment and Production — Quarterlycontractors · production · safety1,002Not published—Not publishedentity-linked
Contractor Employment and Production — Yearlycontractors · production · safety211Not published—Not publishedentity-linked
Controller and Operator Historyidentity · compliance5Jan 1, 1950—Feb 1, 2021mine-keyed
Mine Employment and Production — Quarterlyproduction · safety · compliance318Not published—Not publishedmine-keyed
Mine Employment and Production — Yearlyproduction · safety · compliance81Not published—Not publishedmine-keyed
Inspectionssafety · compliance112May 2, 2000—Sep 9, 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 · safety48Oct 11, 2000—Sep 9, 2026mine-keyed
Noise Sampleshealth · safety · equipment—No published rowsabsent / not applicable
Quartz Samples — Coalhealth · safety—No published rowsabsent / not applicable
Violationscompliance · safety · legal688Oct 3, 2000—Jun 23, 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.