# Relationship history for MSHA mine 2300223

Current hierarchy: **Riverstone Group → Central Stone Company → North Quarry (CS55)**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Riverstone Group → North Quarry (CS55); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** West Lake Quarry & Material Company → North Quarry (CS55); 1950-01-01 to 1991-07-18; source msha-controller-operator-history
- **controller_controls_mine:** William E  Witaker → North Quarry (CS55); 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William E  Witaker → West Lake Quarry & Material Company; 1950-01-01 to 1991-07-18; source msha-controller-operator-history
- **controller_controls_mine:** John H Berra Construction Co → North Quarry (CS55); 1987-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bellefontaine Quarry Inc → North Quarry (CS55); 1991-07-19 to 2001-11-04; source msha-controller-operator-history
- **controller_controls_operator:** John H Berra Construction Co → Bellefontaine Quarry Inc; 1991-07-19 to 2001-11-04; source msha-controller-operator-history
- **operator_operates_mine:** Central Stone Company → North Quarry (CS55); 2001-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Riverstone Group → Central Stone Company; 2001-11-05 to current/open; source msha-controller-operator-history