# Relationship history for MSHA mine 1700621

Current hierarchy: **CRH PLC → Pike Industries Inc → PORTABLE SANDSCREEN C657**

- 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:** BTR PLC → PORTABLE SANDSCREEN C657; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → PORTABLE SANDSCREEN C657; 1988-06-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tilcon Maine Inc → PORTABLE SANDSCREEN C657; 1993-08-01 to 1996-12-31; source msha-controller-operator-history
- **controller_controls_operator:** BTR PLC → Tilcon Maine Inc; 1993-08-01 to 1996-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Pike Industries Inc → PORTABLE SANDSCREEN C657; 1997-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Pike Industries Inc; 1997-01-01 to current/open; source msha-controller-operator-history