# Relationship history for MSHA mine 4608664

Current hierarchy: **Horizon Natural Resources Incorporated → Dunn Coal & Dock Company → Mine No 155 (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

- **controller_controls_mine:** Cyprus Amax Minerals Company → Mine No 155 (1); 1991-11-01 to 1998-06-28; source msha-controller-operator-history
- **operator_operates_mine:** Dunn Coal & Dock Company → Mine No 155 (1); 1997-09-01 to 1998-06-28; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Amax Minerals Company → Dunn Coal & Dock Company; 1997-09-01 to 1998-06-28; source msha-controller-operator-history
- **operator_operates_mine:** Dunn Coal & Dock Company → Mine No 155 (1); 1998-06-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Horizon Natural Resources Incorporated → Mine No 155 (1); 1998-06-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Horizon Natural Resources Incorporated → Dunn Coal & Dock Company; 1998-06-29 to current/open; source msha-controller-operator-history