# Relationship history for MSHA mine 1800410

Current hierarchy: **Aggregate Management, Inc → Laurel Sand & Gravel Inc → Laurel Operation**

- 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:** Contee Sand & Gravel Company Inc → Laurel Operation; 1950-01-01 to 1983-05-01; source msha-controller-operator-history
- **controller_controls_mine:** Contee Resources Inc → Laurel Operation; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Contee Resources Inc → Contee Sand & Gravel Company Inc; 1950-01-01 to 1983-05-01; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Management, Inc → Laurel Operation; 1983-04-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Laurel Sand & Gravel Inc → Laurel Operation; 1983-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Management, Inc → Laurel Sand & Gravel Inc; 1983-05-02 to current/open; source msha-controller-operator-history