# Relationship history for MSHA mine 4601756

Current hierarchy: **Massey Energy Company → Sycamore Fuels Inc → Mine No 1**

- 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:** Smith Brothers Construction Inc → Mine No 1; 1950-01-01 to 1988-06-02; source msha-controller-operator-history
- **controller_controls_mine:** Continental Resources & Mineral Corp → Mine No 1; 1950-01-01 to 1988-06-02; source msha-controller-operator-history
- **controller_controls_operator:** Continental Resources & Mineral Corp → Smith Brothers Construction Inc; 1950-01-01 to 1988-06-02; source msha-controller-operator-history
- **operator_operates_mine:** Preparation Maintenance Inc → Mine No 1; 1988-06-03 to 1990-02-14; source msha-controller-operator-history
- **controller_controls_mine:** Joby  Fields → Mine No 1; 1988-06-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joby  Fields → Preparation Maintenance Inc; 1988-06-03 to 1990-02-14; source msha-controller-operator-history
- **operator_operates_mine:** Sycamore Fuels Inc → Mine No 1; 1990-02-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Massey Energy Company → Mine No 1; 1990-02-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Sycamore Fuels Inc; 1990-02-15 to current/open; source msha-controller-operator-history