# Relationship history for MSHA mine 4605221

Current hierarchy: **Crook Norman E → Trigon 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:** Grandview Mining Inc → No 1 Mine; 1976-04-01 to 1979-04-25; source msha-controller-operator-history
- **controller_controls_mine:** Crook Norman E → No 1 Mine; 1976-04-01 to 1979-04-25; source msha-controller-operator-history
- **controller_controls_operator:** Crook Norman E → Grandview Mining Inc; 1976-04-01 to 1979-04-25; source msha-controller-operator-history
- **operator_operates_mine:** T L K Corp → No 1 Mine; 1979-04-26 to 1979-07-30; source msha-controller-operator-history
- **controller_controls_mine:** Simions Thomas D → No 1 Mine; 1979-04-26 to 1979-07-30; source msha-controller-operator-history
- **controller_controls_operator:** Simions Thomas D → T L K Corp; 1979-04-26 to 1979-07-30; source msha-controller-operator-history
- **operator_operates_mine:** Trigon Corp → No 1 Mine; 1979-07-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Crook Norman E → No 1 Mine; 1979-07-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crook Norman E → Trigon Corp; 1979-07-31 to current/open; source msha-controller-operator-history