# Relationship history for MSHA mine 0504873

Current hierarchy: **Summit Materials LLC → Elam Sand and Gravel → Washplant 1**

- 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:** Harold  Elam → Washplant 1; 1950-01-01 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Marie E  Tipping → Washplant 1; 1987-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Grand Junction Concrete Pipe Company → Washplant 1; 2007-07-18 to 2012-02-23; source msha-controller-operator-history
- **controller_controls_operator:** Marie E  Tipping → Grand Junction Concrete Pipe Company; 2007-07-18 to 2012-02-23; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Washplant 1; 2011-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Elam Sand and Gravel → Washplant 1; 2012-02-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold  Elam → Elam Sand and Gravel; 2012-02-24 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → Elam Sand and Gravel; 2012-02-24 to current/open; source msha-controller-operator-history