# Relationship history for MSHA mine 1800723

Current hierarchy: **English China Clays PLC → Ecci Calcium Products Inc → Ultra Fine Plant Quarry**

- 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:** English China Clays PLC → Ultra Fine Plant Quarry; 1986-10-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Redland Plc → Ultra Fine Plant Quarry; 1986-11-04 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Genstar Stone Products Company → Ultra Fine Plant Quarry; 1990-04-01 to 1995-11-20; source msha-controller-operator-history
- **controller_controls_operator:** Redland Plc → Genstar Stone Products Company; 1990-04-01 to 1995-11-20; source msha-controller-operator-history
- **operator_operates_mine:** Ecci Calcium Products Inc → Ultra Fine Plant Quarry; 1995-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** English China Clays PLC → Ecci Calcium Products Inc; 1995-11-21 to current/open; source msha-controller-operator-history