# Relationship history for MSHA mine 4102598

Current hierarchy: **Cantu Fred → Cantu Materials Inc → Sheppard 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

- **operator_operates_mine:** Conoco Inc → Sheppard Pit; 1950-01-01 to 1988-10-25; source msha-controller-operator-history
- **controller_controls_mine:** Continental Oil Company & Pioneer Nuclear Inc → Sheppard Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Continental Oil Company & Pioneer Nuclear Inc → Conoco Inc; 1950-01-01 to 1988-10-25; source msha-controller-operator-history
- **operator_operates_mine:** Cantu Materials Inc → Sheppard Pit; 1988-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cantu Fred → Sheppard Pit; 1988-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cantu Fred → Cantu Materials Inc; 1988-10-26 to current/open; source msha-controller-operator-history