# Relationship history for MSHA mine 0900886

Current hierarchy: **R H  Bickerstaff → Bickerstaff Clay Products Company Inc → Altizer Pit**

- 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

- **controller_controls_mine:** R H  Bickerstaff → Altizer Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bickerstaff Clay Products Company Inc → Altizer Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** R H  Bickerstaff → Bickerstaff Clay Products Company Inc; 1978-03-09 to current/open; source msha-controller-operator-history