# Relationship history for MSHA mine 0504594

Current hierarchy: **Summit Materials LLC → Elam Construction → HP 300 (Crusher 4)**

- 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 → HP 300 (Crusher 4); 1950-01-01 to 2011-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Snowstorm Sand & Gravel LLC → HP 300 (Crusher 4); 1997-05-01 to 2006-05-15; source msha-controller-operator-history
- **controller_controls_mine:** Vanelscar Snowstorm LLC → HP 300 (Crusher 4); 1997-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vanelscar Snowstorm LLC → Snowstorm Sand & Gravel LLC; 1997-05-01 to 2006-05-15; source msha-controller-operator-history
- **controller_controls_mine:** Tom  Everist → HP 300 (Crusher 4); 2002-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Everist Materials LLC → HP 300 (Crusher 4); 2006-05-16 to 2017-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Everist → Everist Materials LLC; 2006-05-16 to 2017-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → HP 300 (Crusher 4); 2011-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Elam Construction → HP 300 (Crusher 4); 2017-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold  Elam → Elam Construction; 2017-04-01 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → Elam Construction; 2017-04-01 to current/open; source msha-controller-operator-history