# Relationship history for MSHA mine 3606163

Current hierarchy: **Penn Erection & Rigging → Sunset Coal Company Inc → Sunset Strip**

- 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:** Brown Brothers Coal Company → Sunset Strip; 1976-07-12 to 1977-07-21; source msha-controller-operator-history
- **controller_controls_mine:** Brown Fred W & Donald D → Sunset Strip; 1976-07-12 to 1977-07-21; source msha-controller-operator-history
- **controller_controls_operator:** Brown Fred W & Donald D → Brown Brothers Coal Company; 1976-07-12 to 1977-07-21; source msha-controller-operator-history
- **operator_operates_mine:** Sunset Coal Company Inc → Sunset Strip; 1977-07-22 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Penn Erection & Rigging → Sunset Strip; 1977-07-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Penn Erection & Rigging → Sunset Coal Company Inc; 1977-07-22 to current/open; source msha-controller-operator-history