# Relationship history for MSHA mine 2401692

Current hierarchy: **Ballard Al → Special Lady Mining Corp → Pretty Girl Placer**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Ballard Mining Corp → Pretty Girl Placer; 1982-09-01 to 1984-08-27; source msha-controller-operator-history
- **controller_controls_mine:** Ballard Ces → Pretty Girl Placer; 1982-09-01 to 1984-08-27; source msha-controller-operator-history
- **controller_controls_operator:** Ballard Ces → Ballard Mining Corp; 1982-09-01 to 1984-08-27; source msha-controller-operator-history
- **operator_operates_mine:** Impact Resources Inc → Pretty Girl Placer; 1984-08-28 to 1985-06-09; source msha-controller-operator-history
- **controller_controls_mine:** Pneumatic Transportation Systems Inc → Pretty Girl Placer; 1984-08-28 to 1985-06-09; source msha-controller-operator-history
- **controller_controls_operator:** Pneumatic Transportation Systems Inc → Impact Resources Inc; 1984-08-28 to 1985-06-09; source msha-controller-operator-history
- **operator_operates_mine:** Special Lady Mining Corp → Pretty Girl Placer; 1985-06-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ballard Al → Pretty Girl Placer; 1985-06-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ballard Al → Special Lady Mining Corp; 1985-06-10 to current/open; source msha-controller-operator-history