# Relationship history for MSHA mine 2300745

Current hierarchy: **Riverstone Group → Central Stone Company → Fort Bellefontaine (CS31)**

- 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

- **operator_operates_mine:** Missouri Portland Cement Company → Fort Bellefontaine (CS31); 1950-01-01 to 1987-07-13; source msha-controller-operator-history
- **controller_controls_mine:** H K Porter Company Inc → Fort Bellefontaine (CS31); 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** H K Porter Company Inc → Missouri Portland Cement Company; 1950-01-01 to 1987-07-13; source msha-controller-operator-history
- **controller_controls_mine:** Riverstone Group → Fort Bellefontaine (CS31); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Central Stone Company → Fort Bellefontaine (CS31); 1987-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Riverstone Group → Central Stone Company; 1987-07-14 to current/open; source msha-controller-operator-history