# Relationship history for MSHA mine 1509981

Current hierarchy: **Smith Coolidge → Big Nickle Corp → No 1 Mine**

- 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

- **operator_operates_mine:** Tri-Gem Coal Company Inc → No 1 Mine; 1976-09-20 to 1982-08-04; source msha-controller-operator-history
- **controller_controls_mine:** Jimmy E  Hamilton et al → No 1 Mine; 1976-09-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jimmy E  Hamilton et al → Tri-Gem Coal Company Inc; 1976-09-20 to 1982-08-04; source msha-controller-operator-history
- **operator_operates_mine:** Poplar Creek Coal Company → No 1 Mine; 1982-08-05 to 1983-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Bundy Ron Et Al → No 1 Mine; 1982-08-05 to 1983-06-19; source msha-controller-operator-history
- **controller_controls_operator:** Bundy Ron Et Al → Poplar Creek Coal Company; 1982-08-05 to 1983-06-19; source msha-controller-operator-history
- **operator_operates_mine:** Big Nickle Corp → No 1 Mine; 1983-06-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Smith Coolidge → No 1 Mine; 1983-06-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Coolidge → Big Nickle Corp; 1983-06-20 to current/open; source msha-controller-operator-history