# Relationship history for MSHA mine 4605526

Current hierarchy: **Walsh David E → Concord Coal Corp → Clear Creek 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

- **controller_controls_mine:** Walsh David E → Clear Creek No 1; 1976-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Betty Mining Company → Clear Creek No 1; 1977-06-01 to 1978-06-13; source msha-controller-operator-history
- **controller_controls_mine:** Robertson Ed → Clear Creek No 1; 1977-06-01 to 1978-06-13; source msha-controller-operator-history
- **controller_controls_operator:** Robertson Ed → Betty Mining Company; 1977-06-01 to 1978-06-13; source msha-controller-operator-history
- **operator_operates_mine:** Concord Coal Corp → Clear Creek No 1; 1978-06-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walsh David E → Concord Coal Corp; 1978-06-14 to current/open; source msha-controller-operator-history