# Relationship history for MSHA mine 0102694

Current hierarchy: **Dravo Corp → Dravo Basic Materials Company Inc → Selma**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Dravo Corp → Selma; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Alfred Mc Alpine Inc → Selma; 1985-02-06 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R & S Materials Inc → Selma; 1986-08-01 to 1990-01-14; source msha-controller-operator-history
- **controller_controls_operator:** Alfred Mc Alpine Inc → R & S Materials Inc; 1986-08-01 to 1990-01-14; source msha-controller-operator-history
- **operator_operates_mine:** Dravo Basic Materials Company Inc → Selma; 1990-01-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dravo Corp → Dravo Basic Materials Company Inc; 1990-01-15 to current/open; source msha-controller-operator-history