# Relationship history for MSHA mine 4103189

Current hierarchy: **Heidelberg Materials AG → Lehigh Portland Cement Company → SAND SUPPLY INC #3**

- 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:** Heidelberg Materials AG → SAND SUPPLY INC #3; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Voss Gravel Company → SAND SUPPLY INC #3; 1983-07-01 to 1985-05-14; source msha-controller-operator-history
- **controller_controls_mine:** Voss L J → SAND SUPPLY INC #3; 1983-07-01 to 1985-05-14; source msha-controller-operator-history
- **controller_controls_operator:** Voss L J → Voss Gravel Company; 1983-07-01 to 1985-05-14; source msha-controller-operator-history
- **operator_operates_mine:** Sand Supply Inc → SAND SUPPLY INC #3; 1985-05-15 to 1993-03-22; source msha-controller-operator-history
- **controller_controls_mine:** Kurz David M → SAND SUPPLY INC #3; 1985-05-15 to 1993-03-22; source msha-controller-operator-history
- **controller_controls_operator:** Kurz David M → Sand Supply Inc; 1985-05-15 to 1993-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Lehigh Portland Cement Company → SAND SUPPLY INC #3; 1993-03-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Lehigh Portland Cement Company; 1993-03-23 to current/open; source msha-controller-operator-history