# Relationship history for MSHA mine 2301308

Current hierarchy: **CRH PLC → Agrock Quarries Division → Buffalo Quarry**

- 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:** Ash Grove Cement Company → Buffalo Quarry; 1950-01-01 to 2018-06-20; source msha-controller-operator-history
- **operator_operates_mine:** Morgans Material Inc → Buffalo Quarry; 1950-01-01 to 1980-02-29; source msha-controller-operator-history
- **controller_controls_mine:** Morgans Harold E → Buffalo Quarry; 1950-01-01 to 1980-02-29; source msha-controller-operator-history
- **controller_controls_operator:** Morgans Harold E → Morgans Material Inc; 1950-01-01 to 1980-02-29; source msha-controller-operator-history
- **operator_operates_mine:** Agrock Quarries Division → Buffalo Quarry; 1980-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ash Grove Cement Company → Agrock Quarries Division; 1980-03-01 to 2018-06-20; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Buffalo Quarry; 2018-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Agrock Quarries Division; 2018-06-21 to current/open; source msha-controller-operator-history