# Relationship history for MSHA mine 3607888

Current hierarchy: **Asea Brown Boveri Ltd (ABB) → Westwood Energy Properties → Refuse Culm Bank**

- 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:** Grove Coal Company → Refuse Culm Bank; 1987-04-01 to 1987-10-26; source msha-controller-operator-history
- **controller_controls_mine:** Ryan James V → Refuse Culm Bank; 1987-04-01 to 1987-10-26; source msha-controller-operator-history
- **controller_controls_operator:** Ryan James V → Grove Coal Company; 1987-04-01 to 1987-10-26; source msha-controller-operator-history
- **operator_operates_mine:** Westwood Energy Properties → Refuse Culm Bank; 1987-10-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Asea Brown Boveri Ltd (ABB) → Refuse Culm Bank; 1987-10-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Asea Brown Boveri Ltd (ABB) → Westwood Energy Properties; 1987-10-27 to current/open; source msha-controller-operator-history