# Relationship history for MSHA mine 1102551

Current hierarchy: **Riverstone Group → Central Stone Company → Central Stone 21**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Riverstone Group → Central Stone 21; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Omya Quincy Inc → Central Stone 21; 1950-01-01 to 2000-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Omya Industries Inc → Central Stone 21; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Omya Industries Inc → Omya Quincy Inc; 1950-01-01 to 2000-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Central Stone Company → Central Stone 21; 2000-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Riverstone Group → Central Stone Company; 2000-08-01 to current/open; source msha-controller-operator-history