# Relationship history for MSHA mine 2900824

Current hierarchy: **Paul  Parker → Paul Parker Construction → OGLEBAY-NORTON US HILL MINE**

- 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:** Alexander Sand & Gravel → OGLEBAY-NORTON US HILL MINE; 1950-01-01 to 1986-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Richard A  Alexander  et al → OGLEBAY-NORTON US HILL MINE; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard A  Alexander  et al → Alexander Sand & Gravel; 1950-01-01 to 1986-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Paul Parker Construction → OGLEBAY-NORTON US HILL MINE; 1986-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Paul  Parker → OGLEBAY-NORTON US HILL MINE; 1986-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul  Parker → Paul Parker Construction; 1986-11-01 to current/open; source msha-controller-operator-history