# Relationship history for MSHA mine 1510249

Current hierarchy: **United  Company → Wellmore Coal Corp → No 4-A**

- 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:** United  Company → No 4-A; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Donald T → No 4-A; 1973-01-01 to 1977-07-10; source msha-controller-operator-history
- **operator_operates_mine:** Crescent Industries Inc → No 4-A; 1977-03-01 to 1977-07-10; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Donald T → Crescent Industries Inc; 1977-03-01 to 1977-07-10; source msha-controller-operator-history
- **controller_controls_mine:** International Minerals & Chemical Corp → No 4-A; 1977-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Crescent Industries Inc → No 4-A; 1977-07-11 to 1983-02-28; source msha-controller-operator-history
- **controller_controls_operator:** International Minerals & Chemical Corp → Crescent Industries Inc; 1977-07-11 to 1983-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Wellmore Coal Corp → No 4-A; 1983-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** United  Company → Wellmore Coal Corp; 1983-03-01 to current/open; source msha-controller-operator-history