# Relationship history for MSHA mine 0404803

Current hierarchy: **RRM Development Corporation; Mitsubishi Corp → Robertson's → Palmdale**

- 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:** Mitsubishi Corp → Palmdale; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Arrow Rock Materials → Palmdale; 1985-07-01 to 1988-12-01; source msha-controller-operator-history
- **controller_controls_mine:** Frank R  Walker Jr → Palmdale; 1985-07-01 to 1988-12-01; source msha-controller-operator-history
- **controller_controls_operator:** Frank R  Walker Jr → Arrow Rock Materials; 1985-07-01 to 1988-12-01; source msha-controller-operator-history
- **operator_operates_mine:** Service Rock Products → Palmdale; 1988-12-02 to 2010-02-07; source msha-controller-operator-history
- **controller_controls_operator:** Mitsubishi Corp → Service Rock Products; 1988-12-02 to 2010-02-07; source msha-controller-operator-history
- **controller_controls_mine:** RRM Development Corporation et al → Palmdale; 1995-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Robertson's → Palmdale; 2010-02-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** RRM Development Corporation et al → Robertson's; 2010-02-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mitsubishi Corp  et al → Robertson's; 2010-02-08 to current/open; source msha-controller-operator-history