ACTIVE / OPERATOR PORTFOLIO

O-N Minerals (Chemstone Company)

Membership and operating status are from the latest MSHA Mines snapshot. Open a mine for its ownership history.

MSHA OPERATOR IDL16758

MINE PORTFOLIO

5 of 5 mines and facilities

2025-01-01 – 2026-10-17. Active records; production reporting is not required.

MineLocation / typeCoal · short tonsHours workedViolationsAccident recordsOn-site inspection hours
Middletown Quarry4400049 · ActiveFrederick, VASurface · MSHA: Crushed, Broken Limestone NEC——2176.8
Plant #24400064 · ActiveBotetourt, VASurface · MSHA: Crushed, Broken Limestone NEC——0164.3
Rocky Point4400065 · ActiveBotetourt, VASurface · MSHA: Crushed, Broken Limestone NEC——0067.5
Strasburg Quarry4400026 · ActiveShenandoah, VASurface · MSHA: Lime——30125.0
Winchester Plant4400044 · ActiveFrederick, VASurface · MSHA: Lime——40172.3

LOCATION

Portfolio map

5 of 5 mines with usable MSHA coordinates. Select a marker to open a mine.

Mine coordinates

2025-01-01 – 2026-10-17Applies to production, safety and portfolio metrics. Silica samples have separate filters.

Violations

9

0 significant & substantial (S&S)

  1. 2025 Q13
  2. 2025 Q21
  3. 2025 Q31
  4. 2025 Q40
  5. 2026 Q13
  6. 2026 Q21
  7. 2026 Q30
  8. 2026 Q4 *0

Accident records

2

0 records classified as fatality

  1. 2025 Q10
  2. 2025 Q20
  3. 2025 Q30
  4. 2025 Q41
  5. 2026 Q11
  6. 2026 Q20
  7. 2026 Q30
  8. 2026 Q4 *0

Proposed penalties · USD

1,359.00

9 of 9 violations with amounts

  1. 2025 Q1453
  2. 2025 Q2151
  3. 2025 Q3151
  4. 2025 Q4—
  5. 2026 Q1453
  6. 2026 Q2151
  7. 2026 Q3—
  8. 2026 Q4 *—

On-site inspection hours

505.75

22 inspections · 22 with hours

  1. 2025 Q178.75
  2. 2025 Q2150.25
  3. 2025 Q321.50
  4. 2025 Q4—
  5. 2026 Q1109.50
  6. 2026 Q268.75
  7. 2026 Q377.00
  8. 2026 Q4 *—
Quarterly safety data
QuarterViolationsS&SProposed USDAccident recordsFatality recordsInspectionsOn-site hours
2025-Q130453.0000478.8
2025-Q210151.00005150.3
2025-Q310151.0000221.5
2025-Q400—100—
2026-Q130453.00105109.5
2026-Q210151.0000368.8
2026-Q300—00377.0
2026-Q4 *00—000—

Most cited CFR sections

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

Safety activity

  1. inspectionF02A6B1
    Plant #2 · 4400064

    Non-Chargeable Accident Investigation · 2.0 on-site hours

  2. inspectionF009796
    Strasburg Quarry · 4400026

    Regular Safety and Health Inspection · 30.0 on-site hours

  3. inspectionF009792
    Winchester Plant · 4400044

    Regular Safety and Health Inspection · 45.0 on-site hours

  4. violation8284134
    Middletown Quarry · 4400049

    56.14100(b) · $151.00 proposed

  5. inspectionF00978F
    Middletown Quarry · 4400049

    Regular Safety and Health Inspection · 15.0 on-site hours

  6. inspectionF0249DB
    Rocky Point · 4400065

    Regular Safety and Health Inspection · 23.0 on-site hours

  7. inspectionF0249DA
    Plant #2 · 4400064

    Regular Safety and Health Inspection · 30.8 on-site hours

  8. violation8281943
    Winchester Plant · 4400044

    56.12004 · $151.00 proposed

  9. violation8281942
    Winchester Plant · 4400044

    56.12032 · $151.00 proposed

  10. inspectionF010E50
    Winchester Plant · 4400044

    Regular Safety and Health Inspection · 42.5 on-site hours

  11. inspectionF00977F
    Middletown Quarry · 4400049

    Regular Safety and Health Inspection · 18.0 on-site hours

  12. violation8281937
    Strasburg Quarry · 4400026

    56.14112(b) · $151.00 proposed

  13. inspectionF010E4D
    Strasburg Quarry · 4400026

    Regular Safety and Health Inspection · 24.0 on-site hours

  14. accident220260400031
    Plant #2 · 4400064

    HANDTOOLS (NONPOWERED) · NO DYS AWY FRM WRK,NO RSTR ACT

    Accident narrative

    EE states that while using a pocketknife to cut tape, the blade did not lock fully and folded into left hand resulting in a small cut. The EE was taken to urgent care which resulted in the application of 1 stitch.

  15. inspectionF00603F
    Plant #2 · 4400064

    Regular Safety and Health Inspection · 10.5 on-site hours

  16. inspectionF00603E
    Rocky Point · 4400065

    Regular Safety and Health Inspection · 14.5 on-site hours

  17. accident220260120002
    Middletown Quarry · 4400049

    SLIP OR FALL OF PERSON · DAYS RESTRICTED ACTIVITY ONLY

    Accident narrative

    EE states that while pulling water hose to back to hose reel on water truck that the EE's foot hooked a frozen clump of material, causing a fall to the ground on EE's left side. EE was seen at urgent care and was issued restrictions due to limited mobility and pain in left shoulder and left thigh.

  18. inspectionF006037
    Strasburg Quarry · 4400026

    Spot Inspection · 11.0 on-site hours

  19. inspectionF0293BE
    Middletown Quarry · 4400049

    Spot Inspection · 10.5 on-site hours

  20. violation8281932
    Strasburg Quarry · 4400026

    56.12008 · $151.00 proposed

  21. inspectionF00BC6F
    Strasburg Quarry · 4400026

    Regular Safety and Health Inspection · 36.5 on-site hours

  22. violation8281924
    Winchester Plant · 4400044

    56.14100(b) · $151.00 proposed

  23. inspectionF00BC6C
    Winchester Plant · 4400044

    Regular Safety and Health Inspection · 55.8 on-site hours

  24. inspection4135559
    Plant #2 · 4400064

    Regular Safety and Health Inspection · 21.0 on-site hours

  25. inspectionF00BC69
    Middletown Quarry · 4400049

    Regular Safety and Health Inspection · 19.0 on-site hours

Safety sources and definitions

MSHA Violations (issue date), Accidents (accident date), and Inspections (begin date). Snapshot 2026-10-17.

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

1 linked controller.

Relationships reflect the selected mine status and current MSHA controller/operator fields.