# Relationship history for MSHA mine 1301880

Current hierarchy: **CRH PLC → Hallett Materials → CHEROKEE NORTH**

- 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

- **operator_operates_mine:** Cherokee County Highway Department → CHEROKEE NORTH; 1979-01-01 to 1980-10-26; source msha-controller-operator-history
- **controller_controls_mine:** Cherokee County-IA → CHEROKEE NORTH; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cherokee County-IA → Cherokee County Highway Department; 1979-01-01 to 1980-10-26; source msha-controller-operator-history
- **operator_operates_mine:** Walker Sand & Gravel Company → CHEROKEE NORTH; 1980-10-27 to 1991-04-23; source msha-controller-operator-history
- **controller_controls_mine:** Keith  Walker → CHEROKEE NORTH; 1980-10-27 to 1991-04-23; source msha-controller-operator-history
- **controller_controls_operator:** Keith  Walker → Walker Sand & Gravel Company; 1980-10-27 to 1991-04-23; source msha-controller-operator-history
- **controller_controls_mine:** Mid America Materials Company → CHEROKEE NORTH; 1986-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Materials → CHEROKEE NORTH; 1991-04-24 to 1999-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Mid America Materials Company → Hallett Materials; 1991-04-24 to 1999-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Materials → CHEROKEE NORTH; 1999-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rasmussen Group Inc → CHEROKEE NORTH; 1999-04-01 to 2001-08-10; source msha-controller-operator-history
- **controller_controls_operator:** Rasmussen Group Inc → Hallett Materials; 1999-04-01 to 2001-08-10; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → CHEROKEE NORTH; 2001-08-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Hallett Materials; 2001-08-11 to current/open; source msha-controller-operator-history