# Relationship history for MSHA mine 1300766

Current hierarchy: **CRH PLC → Cessford Construction Company → Spring Sand Plant**

- 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:** Raid Quarries Division → Spring Sand Plant; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Medusa Corp → Spring Sand Plant; 1950-01-01 to 1979-04-05; source msha-controller-operator-history
- **controller_controls_operator:** Medusa Corp → Raid Quarries Division; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Heidi Cessford  Krabbe et al → Spring Sand Plant; 1950-01-01 to 2007-08-23; source msha-controller-operator-history
- **controller_controls_mine:** Crane Company → Spring Sand Plant; 1978-12-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Medusa Aggregates Company → Spring Sand Plant; 1979-01-01 to 1980-10-06; source msha-controller-operator-history
- **controller_controls_operator:** Crane Company → Medusa Aggregates Company; 1979-01-01 to 1980-10-06; source msha-controller-operator-history
- **operator_operates_mine:** Cessford Construction Company → Spring Sand Plant; 1980-10-07 to 2008-01-08; source msha-controller-operator-history
- **controller_controls_operator:** Heidi Cessford  Krabbe et al → Cessford Construction Company; 1980-10-07 to 2007-08-23; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Spring Sand Plant; 2007-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Cessford Construction Company; 2007-08-24 to 2008-01-08; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Spring Sand Plant; 2008-01-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Cessford Construction Company → Spring Sand Plant; 2008-01-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Cessford Construction Company; 2008-01-09 to current/open; source msha-controller-operator-history