# Relationship history for MSHA mine 1509440

Current hierarchy: **Smith Daniel F → Kentucky Heritage Coal Inc → No 3 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Burgett Coal Company → No 3 Mine; 1976-01-01 to 1978-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Burgett John → No 3 Mine; 1976-01-01 to 1978-05-08; source msha-controller-operator-history
- **controller_controls_operator:** Burgett John → Burgett Coal Company; 1976-01-01 to 1978-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Smith Daniel F → No 3 Mine; 1977-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Heritage Coal Inc → No 3 Mine; 1978-05-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Daniel F → Kentucky Heritage Coal Inc; 1978-05-09 to current/open; source msha-controller-operator-history