# Relationship history for MSHA mine 3601939

Current hierarchy: **Harner Leonard & Jackson → Okay Coal Company → Orchard Slope 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:** P & M Coal Co → Orchard Slope Mine; 1950-01-01 to 1974-10-10; source msha-controller-operator-history
- **controller_controls_mine:** P & M Coal Company → Orchard Slope Mine; 1950-01-01 to 1974-10-10; source msha-controller-operator-history
- **controller_controls_operator:** P & M Coal Company → P & M Coal Co; 1950-01-01 to 1974-10-10; source msha-controller-operator-history
- **operator_operates_mine:** Okay Coal Company → Orchard Slope Mine; 1974-10-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harner Leonard & Jackson Et Al → Orchard Slope Mine; 1974-10-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harner Leonard & Jackson Et Al → Okay Coal Company; 1974-10-11 to current/open; source msha-controller-operator-history