# Relationship history for MSHA mine 1507905

Current hierarchy: **Summers-Ruby Coal - J/V → Summers-Ruby Coal - J/V → Happy Dutches 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:** R E Summers Construction Company Inc → Happy Dutches Strip; 1974-11-01 to 1975-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Summers R E → Happy Dutches Strip; 1974-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Summers R E → R E Summers Construction Company Inc; 1974-11-01 to 1975-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Summers-Ruby Coal - J/V → Happy Dutches Strip; 1975-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Summers-Ruby Coal - J/V → Happy Dutches Strip; 1975-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Summers-Ruby Coal - J/V → Summers-Ruby Coal - J/V; 1975-07-01 to current/open; source msha-controller-operator-history