# Relationship history for MSHA mine 0503213

Current hierarchy: **Redland Plc → Sterling Sand & Gravel Company → W R E N**

- 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:** Sterling W A → W R E N; 1950-01-01 to 1981-11-14; source msha-controller-operator-history
- **controller_controls_mine:** Koppers Co Inc & Redland Plc → W R E N; 1950-01-01 to 1988-06-13; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel Company → W R E N; 1978-03-09 to 1981-11-14; source msha-controller-operator-history
- **controller_controls_operator:** Sterling W A → Sterling Sand & Gravel Company; 1978-03-09 to 1981-11-14; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel Company → W R E N; 1981-11-15 to 1987-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Koppers Company Inc → W R E N; 1981-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Sterling Sand & Gravel Company; 1981-11-15 to 1987-04-19; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel Company → W R E N; 1987-04-20 to 1988-06-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Co Inc & Redland Plc → Sterling Sand & Gravel Company; 1987-04-20 to 1988-06-13; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Sand & Gravel Company → W R E N; 1988-06-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Redland Plc → W R E N; 1988-06-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Redland Plc → Sterling Sand & Gravel Company; 1988-06-14 to current/open; source msha-controller-operator-history