# Relationship history for MSHA mine 1500010

Current hierarchy: **John C  Albright → Camp Nelson Stone Company Inc → Camp Nelson Stone Company Incorporated**

- 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:** Camp Nelson Stone Company Inc → Camp Nelson Stone Company Incorporated; 1950-01-01 to 1979-01-10; source msha-controller-operator-history
- **controller_controls_mine:** Grubbs Roger → Camp Nelson Stone Company Incorporated; 1950-01-01 to 1979-01-10; source msha-controller-operator-history
- **controller_controls_operator:** Grubbs Roger → Camp Nelson Stone Company Inc; 1950-01-01 to 1979-01-10; source msha-controller-operator-history
- **operator_operates_mine:** Camp Nelson Stone Company Inc → Camp Nelson Stone Company Incorporated; 1979-01-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John C  Albright → Camp Nelson Stone Company Incorporated; 1979-01-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John C  Albright → Camp Nelson Stone Company Inc; 1979-01-11 to current/open; source msha-controller-operator-history