# Relationship history for MSHA mine 4103267

Current hierarchy: **Carolyn  Morris; Jeff  Korus → Palo Alto Silica Sand Inc → PALO ALTO PLANT #2**

- 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:** Palo Alto Sand Company Inc → PALO ALTO PLANT #2; 1984-10-01 to 1996-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Jack D Harrison → PALO ALTO PLANT #2; 1984-10-01 to 1996-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Jack D Harrison → Palo Alto Sand Company Inc; 1984-10-01 to 1996-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Jeff  Korus et al → PALO ALTO PLANT #2; 1993-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Palo Alto Silica Sand Inc → PALO ALTO PLANT #2; 1996-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeff  Korus et al → Palo Alto Silica Sand Inc; 1996-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carolyn  Morris et al → Palo Alto Silica Sand Inc; 1996-07-10 to current/open; source msha-controller-operator-history