# Relationship history for MSHA mine 3400679

Current hierarchy: **Kenneth K  Wert → General Materials Inc → Macarthur Sand Plant**

- 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

- **operator_operates_mine:** Sand Products Corp → Macarthur Sand Plant; 1950-01-01 to 1979-06-12; source msha-controller-operator-history
- **controller_controls_mine:** Katherine  Stanford → Macarthur Sand Plant; 1950-01-01 to 1979-06-12; source msha-controller-operator-history
- **controller_controls_operator:** Katherine  Stanford → Sand Products Corp; 1950-01-01 to 1979-06-12; source msha-controller-operator-history
- **controller_controls_mine:** Larry H  Lemon  et al → Macarthur Sand Plant; 1979-05-01 to 2009-12-03; source msha-controller-operator-history
- **operator_operates_mine:** General Materials Inc → Macarthur Sand Plant; 1979-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry H  Lemon  et al → General Materials Inc; 1979-06-13 to 2009-12-03; source msha-controller-operator-history
- **controller_controls_mine:** Kenneth K  Wert → Macarthur Sand Plant; 2009-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth K  Wert → General Materials Inc; 2009-12-04 to current/open; source msha-controller-operator-history