# Relationship history for MSHA mine 1516954

Current hierarchy: **Hammond Bill → Newberry Mining → 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:** Hard Dollar Coal Company Inc → No 1; 1990-09-01 to 1992-10-05; source msha-controller-operator-history
- **controller_controls_mine:** Abbott Floyd → No 1; 1990-09-01 to 1992-10-05; source msha-controller-operator-history
- **controller_controls_operator:** Abbott Floyd → Hard Dollar Coal Company Inc; 1990-09-01 to 1992-10-05; source msha-controller-operator-history
- **operator_operates_mine:** Newberry Mining → No 1; 1992-10-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hammond Bill → No 1; 1992-10-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hammond Bill → Newberry Mining; 1992-10-06 to current/open; source msha-controller-operator-history