# Relationship history for MSHA mine 4401862

Current hierarchy: **M A Hanna Company; W R Grace Company → Rapoca Energy Company → No 3 Prep Plant**

- 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:** Black Watch Coal Corp → No 3 Prep Plant; 1950-01-01 to 1976-03-29; source msha-controller-operator-history
- **controller_controls_mine:** Fields Resources Inc → No 3 Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fields Resources Inc → Black Watch Coal Corp; 1950-01-01 to 1976-03-29; source msha-controller-operator-history
- **controller_controls_mine:** Excello Coal Corp → No 3 Prep Plant; 1975-08-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Excello Coal Corp → No 3 Prep Plant; 1976-03-30 to 1977-12-18; source msha-controller-operator-history
- **controller_controls_operator:** Excello Coal Corp → Excello Coal Corp; 1976-03-30 to 1977-12-18; source msha-controller-operator-history
- **operator_operates_mine:** Black Watch/Black Diamond Coal Corp → No 3 Prep Plant; 1977-12-19 to 1980-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Fields Resources Inc → Black Watch/Black Diamond Coal Corp; 1977-12-19 to 1980-06-30; source msha-controller-operator-history
- **controller_controls_mine:** M A Hanna Company et al → No 3 Prep Plant; 1980-06-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rapoca Energy Company → No 3 Prep Plant; 1980-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** M A Hanna Company et al → Rapoca Energy Company; 1980-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W R Grace Company et al → Rapoca Energy Company; 1980-07-01 to current/open; source msha-controller-operator-history