# Relationship history for MSHA mine 1508623

Current hierarchy: **Gibson Hershel → Pine Ridge Processing Inc → No 1 Preparation Plant**

- 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:** Quality Processing → No 1 Preparation Plant; 1975-02-01 to 1978-05-02; source msha-controller-operator-history
- **controller_controls_mine:** Collins Carl & Johnnie Franks → No 1 Preparation Plant; 1975-02-01 to 1978-05-02; source msha-controller-operator-history
- **controller_controls_operator:** Collins Carl & Johnnie Franks → Quality Processing; 1975-02-01 to 1978-05-02; source msha-controller-operator-history
- **operator_operates_mine:** Quality Processing Inc → No 1 Preparation Plant; 1978-05-03 to 1979-10-15; source msha-controller-operator-history
- **controller_controls_mine:** Sigmon Harold A → No 1 Preparation Plant; 1978-05-03 to 1979-10-15; source msha-controller-operator-history
- **controller_controls_operator:** Sigmon Harold A → Quality Processing Inc; 1978-05-03 to 1979-10-15; source msha-controller-operator-history
- **operator_operates_mine:** Pine Ridge Processing Inc → No 1 Preparation Plant; 1979-10-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gibson Hershel → No 1 Preparation Plant; 1979-10-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gibson Hershel → Pine Ridge Processing Inc; 1979-10-16 to current/open; source msha-controller-operator-history