Coal production
0reported short tons
ACTIVE / CONTROLLER PORTFOLIO
Brent Gerken; Michael J Gerken
Membership and operating status are from the latest MSHA Mines snapshot. Open a mine for its ownership history.
MSHA CONTROLLER IDM08470
MINE PORTFOLIO
7 of 7 mines and facilities
2025-01-01 – 2026-10-18. Active records; production reporting is not required.
Material, method and type filters apply to this table. The portfolio’s status applies to the entire page. GEM fields describe their own release, not the selected MSHA year.
| Mine | Location / type | Coal · short tons | Hours worked | Violations | Accident records | On-site inspection hours |
|---|---|---|---|---|---|---|
| Bluffton Stone Company LLC.3300017 · Active6/8 quarters reported | Allen, OHSurface · MSHA: Crushed, Broken Limestone NEC | 0 | 49,363 | 9 | 0 | 46.0 |
| Clinton Plant2002886 · Active6/8 quarters reported | Washtenaw, MISurface · MSHA: Construction Sand and Gravel | 0 | 21,875 | 1 | 1 | 40.8 |
| Custar Stone Company3300143 · Active6/8 quarters reported | Wood, OHSurface · MSHA: Crushed, Broken Limestone NEC | 0 | 42,114 | 6 | 2 | 54.5 |
| Gerken Materials- Hillsdale Plant2002344 · Active6/8 quarters reported | Hillsdale, MISurface · MSHA: Construction Sand and Gravel | 0 | 17,326 | 3 | 1 | 35.8 |
| Gerken Materials Inc3300033 · Active6/8 quarters reported | Wood, OHSurface · MSHA: Crushed, Broken Limestone NEC | 0 | 25,258 | 2 | 0 | 31.5 |
| Round Lake Sand and Gravel West Plt2003447 · Active6/8 quarters reported | Lenawee, MISurface · MSHA: Construction Sand and Gravel | 0 | 27,346 | 3 | 1 | 28.3 |
| Tecumseh Plant2003312 · Active6/8 quarters reported | Lenawee, MISurface · MSHA: Construction Sand and Gravel | 0 | 16,230 | 1 | 0 | 18.0 |
Production and hours sum available quarterly reports. — means unavailable; zero safety records means none in the selected imported period. Ownership reflects the current MSHA record.
LOCATION
Portfolio map
7 of 7 mines with usable MSHA coordinates. Select a marker to open a mine.
Mine coordinates
- Bluffton Stone Company LLC.40.88917, -83.89028Open map ↗
- Clinton Plant42.09472, -83.98806Open map ↗
- Custar Stone Company41.32833, -83.87833Open map ↗
- Gerken Materials- Hillsdale Plant41.75778, -84.51500Open map ↗
- Gerken Materials Inc41.24000, -83.48750Open map ↗
- Round Lake Sand and Gravel West Plt42.02972, -84.27694Open map ↗
- Tecumseh Plant41.97750, -83.98389Open map ↗
Quarterly trends
2025 Q1 – 2026 Q4
Database snapshot · 2026-10-18. All 7 mines listed under this controller were checked; 7 have reports in the available quarters. Totals use current ownership.
Hours worked
199,512reported 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 | 27,863 | 0.00 | 58 | 7/7 mines reporting |
| 2025 Q2 | 0 | 38,515 | 0.00 | 67 | 7/7 mines reporting |
| 2025 Q3 | 0 | 40,654 | 0.00 | 65 | 7/7 mines reporting |
| 2025 Q4 | 0 | 34,434 | 0.00 | 65 | 7/7 mines reporting |
| 2026 Q1 | 0 | 22,764 | 0.00 | 56 | 7/7 mines reporting |
| 2026 Q2 | 0 | 35,282 | 0.00 | 64 | 7/7 mines reporting |
| 2026 Q3 | — | — | — | — | No report |
| 2026 Q4 | — | — | — | — | No report |
Safety and enforcement
2025-01-01 – 2026-10-18
Violations
255 significant & substantial (S&S)
Accident records
50 records classified as fatality
Proposed penalties · USD
4,356.0023 of 25 violations with amounts
On-site inspection hours
254.7526 inspections · 26 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 | 151.00 | 1 | 0 | 3 | 23.3 |
| 2025-Q2 | 9 | 1 | 1,606.00 | 1 | 0 | 7 | 74.3 |
| 2025-Q3 | 0 | 0 | — | 0 | 0 | 2 | 21.3 |
| 2025-Q4 | 2 | 0 | 302.00 | 0 | 0 | 4 | 35.3 |
| 2026-Q1 | 2 | 1 | 302.00 | 2 | 0 | 3 | 34.3 |
| 2026-Q2 | 11 | 3 | 1,995.00 | 0 | 0 | 5 | 54.5 |
| 2026-Q3 | 0 | 0 | — | 1 | 0 | 2 | 12.0 |
| 2026-Q4 * | 0 | 0 | — | 0 | 0 | 0 | — |
Most cited CFR sections
All violations issued in the selected period. Counts combine subsections.
Safety activity
- Gerken Materials Inc · 3300033
Regular Safety and Health Inspection · 10.0 on-site hours
- Bluffton Stone Company LLC. · 3300017
Regular Safety and Health Inspection · 8.5 on-site hours
- Bluffton Stone Company LLC. · 3300017
56.12028 · $151.00 proposed
- Clinton Plant · 2002886
Regular Safety and Health Inspection · 14.8 on-site hours
- Round Lake Sand and Gravel West Plt · 2003447
Regular Safety and Health Inspection · 6.0 on-site hours
- Tecumseh Plant · 2003312
Regular Safety and Health Inspection · 6.0 on-site hours
- Tecumseh Plant · 2003312
56.4501 · $151.00 proposed
- Gerken Materials- Hillsdale Plant · 2002344
Spot Inspection · 10.8 on-site hours
- Clinton Plant · 2002886
Regular Safety and Health Inspection · 10.5 on-site hours
- Bluffton Stone Company LLC. · 3300017
56.14100(a) · $151.00 proposed
- Bluffton Stone Company LLC. · 3300017
56.14101(a)(2) · $151.00 proposed
- Bluffton Stone Company LLC. · 3300017
56.14112(a)(1) · $151.00 proposed
- Bluffton Stone Company LLC. · 3300017
56.12032 · $151.00 proposed
- Bluffton Stone Company LLC. · 3300017
Regular Safety and Health Inspection · 20.5 on-site hours
- Custar Stone Company · 3300143
Compliance Follow-up Inspection · 1.8 on-site hours
- Custar Stone Company · 3300143
56.11001 · S&S · $549.00 proposed
- Custar Stone Company · 3300143
56.14100(b) · $151.00 proposed
- Custar Stone Company · 3300143
HANDLING OF MATERIALS · DAYS AWAY FROM WORK ONLY
Accident narrative
Employee was filling water tanks on back of truck. Water pressure was too high and employee lost control of hose causing them to lose balance and fell off the side of the truck. When employee fell they struck their head on the concrete knocking them unconscious.
- Custar Stone Company · 3300143
Regular Safety and Health Inspection · 16.5 on-site hours
- Custar Stone Company · 3300143
Description not reported
- Gerken Materials- Hillsdale Plant · 2002344
Regular Safety and Health Inspection · 9.5 on-site hours
- Gerken Materials Inc · 3300033
Regular Safety and Health Inspection · 7.3 on-site hours
- Gerken Materials- Hillsdale Plant · 2002344
56.12018 · $151.00 proposed
- Round Lake Sand and Gravel West Plt · 2003447
56.14132(a) · $151.00 proposed
- Round Lake Sand and Gravel West Plt · 2003447
Regular Safety and Health Inspection · 10.8 on-site hours
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.
SELECTED PORTFOLIO
3 linked operators.
Relationships reflect the selected mine status and current MSHA controller/operator fields.