# Relationship history for MSHA mine 1302177

Current hierarchy: **CRH PLC → Hallett Materials → Port. Plant #7 & #2 Stripping Crew**

- 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

- **controller_controls_mine:** Mid America Materials Company → Port. Plant #7 & #2 Stripping Crew; 1986-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Materials → Port. Plant #7 & #2 Stripping Crew; 1990-04-01 to 1999-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Mid America Materials Company → Hallett Materials; 1990-04-01 to 1999-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Materials → Port. Plant #7 & #2 Stripping Crew; 1999-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rasmussen Group Inc → Port. Plant #7 & #2 Stripping Crew; 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 → Port. Plant #7 & #2 Stripping Crew; 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