# Relationship history for MSHA mine 3400826

Current hierarchy: **Caughern Ray → Caughern Construction Company → Portable Plant No 1**

- 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:** Arkhola Sand & Gravel Company → Portable Plant No 1; 1950-01-01 to 1996-01-15; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc → Portable Plant No 1; 1950-01-01 to 2006-08-27; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc → Arkhola Sand & Gravel Company; 1950-01-01 to 1996-01-15; source msha-controller-operator-history
- **operator_operates_mine:** Caughern Construction Company → Portable Plant No 1; 1996-01-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Caughern Ray → Portable Plant No 1; 1996-01-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Caughern Ray → Caughern Construction Company; 1996-01-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Portable Plant No 1; 2006-08-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Arkhola Sand & Gravel Company; 2006-08-28 to 1996-01-15; source msha-controller-operator-history