# Relationship history for MSHA mine 2301276

Current hierarchy: **List & Clark Construction Company → Holliday Sand & Gravel Company → LIBERTY BEND PLANT #12**

- 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

- **controller_controls_mine:** Peter E  Powell → LIBERTY BEND PLANT #12; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** List & Clark Construction Company → LIBERTY BEND PLANT #12; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Liberty Bend Sand Company → LIBERTY BEND PLANT #12; 1950-01-01 to 1987-02-04; source msha-controller-operator-history
- **controller_controls_mine:** Clarkson Construction Co et al → LIBERTY BEND PLANT #12; 1950-01-01 to 1990-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Clarkson Construction Co et al → Liberty Bend Sand Company; 1950-01-01 to 1987-02-04; source msha-controller-operator-history
- **operator_operates_mine:** Builders Sand Company → LIBERTY BEND PLANT #12; 1987-02-05 to 1988-01-01; source msha-controller-operator-history
- **controller_controls_operator:** Peter E  Powell → Builders Sand Company; 1987-02-05 to 1988-01-01; source msha-controller-operator-history
- **operator_operates_mine:** Liberty Bend Sand Company → LIBERTY BEND PLANT #12; 1988-01-02 to 1990-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Clarkson Construction Co et al → Liberty Bend Sand Company; 1988-01-02 to 1990-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Holliday Sand & Gravel Company → LIBERTY BEND PLANT #12; 1990-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** List & Clark Construction Company → Holliday Sand & Gravel Company; 1990-06-01 to current/open; source msha-controller-operator-history