# Relationship history for MSHA mine 2602138

Current hierarchy: **David W  Rice → Rice Construction → Westside Sand and Gravel**

- 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

- **operator_operates_mine:** Quality Sand & Gravel → Westside Sand and Gravel; 1990-01-01 to 2002-03-02; source msha-controller-operator-history
- **controller_controls_mine:** Vosburg Gary → Westside Sand and Gravel; 1990-01-01 to 2002-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Vosburg Gary → Quality Sand & Gravel; 1990-01-01 to 2002-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Mike A  Hickey → Westside Sand and Gravel; 1998-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mike A  Hickey → Westside Sand and Gravel; 2002-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mike A  Hickey → Quality Sand & Gravel; 2002-02-01 to 2002-03-02; source msha-controller-operator-history
- **operator_operates_mine:** Bulldog Equipment → Westside Sand and Gravel; 2002-03-03 to 2011-02-23; source msha-controller-operator-history
- **controller_controls_operator:** Mike A  Hickey → Bulldog Equipment; 2002-03-03 to 2011-02-23; source msha-controller-operator-history
- **operator_operates_mine:** Rice Construction → Westside Sand and Gravel; 2011-02-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David W  Rice → Westside Sand and Gravel; 2011-02-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David W  Rice → Rice Construction; 2011-02-24 to current/open; source msha-controller-operator-history