# Relationship history for MSHA mine 4103184

Current hierarchy: **Lower Colorado River Authority → Lower Colorado River Authority → Powell Bend 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Bastrop Mining Company Inc → Powell Bend Mine; 1983-07-01 to 1986-06-03; source msha-controller-operator-history
- **controller_controls_mine:** Washington Group International Inc → Powell Bend Mine; 1983-07-01 to 1986-06-03; source msha-controller-operator-history
- **controller_controls_operator:** Washington Group International Inc → Bastrop Mining Company Inc; 1983-07-01 to 1986-06-03; source msha-controller-operator-history
- **controller_controls_mine:** Lower Colorado River Authority → Powell Bend Mine; 1984-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lower Colorado River Authority → Powell Bend Mine; 1986-06-04 to 1987-04-09; source msha-controller-operator-history
- **controller_controls_operator:** Lower Colorado River Authority → Lower Colorado River Authority; 1986-06-04 to 1987-04-09; source msha-controller-operator-history
- **operator_operates_mine:** Powell Bend Mining Company → Powell Bend Mine; 1987-04-10 to 1991-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Chevron Corporation → Powell Bend Mine; 1987-04-10 to 1991-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Chevron Corporation → Powell Bend Mining Company; 1987-04-10 to 1991-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Lower Colorado River Authority → Powell Bend Mine; 1991-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lower Colorado River Authority → Lower Colorado River Authority; 1991-11-01 to current/open; source msha-controller-operator-history