# Relationship history for MSHA mine 4001288

Current hierarchy: **Laco Inc-H & B Mining & Coal Services → Laco Mining Company → No 1 Strip**

- 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:** Ewell L Spradlin Coal Company → No 1 Strip; 1950-01-01 to 1973-12-09; source msha-controller-operator-history
- **controller_controls_mine:** Spradlin Ewell L → No 1 Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Spradlin Ewell L → Ewell L Spradlin Coal Company; 1950-01-01 to 1973-12-09; source msha-controller-operator-history
- **operator_operates_mine:** Laco Mining Company → No 1 Strip; 1973-12-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Laco Inc-H & B Mining & Coal Services → No 1 Strip; 1973-12-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Laco Inc-H & B Mining & Coal Services → Laco Mining Company; 1973-12-10 to current/open; source msha-controller-operator-history