# Relationship history for MSHA mine 1508295

Current hierarchy: **T W Oil Inc → Joc Coal Mining Inc → No 4 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

- **controller_controls_mine:** Simpson James W → No 4 Mine; 1973-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Skyuka Mining Corp → No 4 Mine; 1975-04-01 to 1975-07-27; source msha-controller-operator-history
- **controller_controls_operator:** Simpson James W → Skyuka Mining Corp; 1975-04-01 to 1975-07-27; source msha-controller-operator-history
- **operator_operates_mine:** Joc Coal Mining Inc → No 4 Mine; 1975-07-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** T W Oil Inc → No 4 Mine; 1975-07-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** T W Oil Inc → Joc Coal Mining Inc; 1975-07-28 to current/open; source msha-controller-operator-history