# Relationship history for MSHA mine 4605790

Current hierarchy: **Harper Dice → Ablution Coals Inc → No 1 Preparation 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Carbotec Coal Services → No 1 Preparation Plant; 1978-05-01 to 1979-06-06; source msha-controller-operator-history
- **controller_controls_mine:** Nightingale E Richard → No 1 Preparation Plant; 1978-05-01 to 1980-10-27; source msha-controller-operator-history
- **controller_controls_operator:** Nightingale E Richard → Carbotec Coal Services; 1978-05-01 to 1979-06-06; source msha-controller-operator-history
- **operator_operates_mine:** N R G Development Company → No 1 Preparation Plant; 1979-06-07 to 1979-11-01; source msha-controller-operator-history
- **controller_controls_mine:** Mickelson G H & Melvin--Dick Cahoone → No 1 Preparation Plant; 1979-06-07 to 1979-11-01; source msha-controller-operator-history
- **controller_controls_operator:** Mickelson G H & Melvin--Dick Cahoone → N R G Development Company; 1979-06-07 to 1979-11-01; source msha-controller-operator-history
- **operator_operates_mine:** Carbotec Coal Services → No 1 Preparation Plant; 1979-11-02 to 1980-10-27; source msha-controller-operator-history
- **controller_controls_operator:** Nightingale E Richard → Carbotec Coal Services; 1979-11-02 to 1980-10-27; source msha-controller-operator-history
- **operator_operates_mine:** Ablution Coals Inc → No 1 Preparation Plant; 1980-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harper Dice → No 1 Preparation Plant; 1980-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harper Dice → Ablution Coals Inc; 1980-10-28 to current/open; source msha-controller-operator-history