# Relationship history for MSHA mine 1513044

Current hierarchy: **Howell Corporation → Lake Coal Company Inc → Tolby Branch No 1 Surface**

- 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:** Howell Corporation → Tolby Branch No 1 Surface; 1977-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** W & S Coal Company → Tolby Branch No 1 Surface; 1981-08-01 to 1984-08-07; source msha-controller-operator-history
- **controller_controls_mine:** Whitaker Ova & Joe Smith → Tolby Branch No 1 Surface; 1981-08-01 to 1984-08-07; source msha-controller-operator-history
- **controller_controls_operator:** Whitaker Ova & Joe Smith → W & S Coal Company; 1981-08-01 to 1984-08-07; source msha-controller-operator-history
- **operator_operates_mine:** Lake Coal Company Inc → Tolby Branch No 1 Surface; 1984-08-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Howell Corporation → Lake Coal Company Inc; 1984-08-08 to current/open; source msha-controller-operator-history