# Relationship history for MSHA mine 2902370

Current hierarchy: **Valley Improvement Association → South Valley Development Corp → Albert Hill**

- 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:** William T Stone → Albert Hill; 1950-01-01 to 2004-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Valley Improvement Association → Albert Hill; 2004-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Belen Sand & Gravel Co Inc → Albert Hill; 2008-04-11 to 2008-08-04; source msha-controller-operator-history
- **controller_controls_operator:** Valley Improvement Association → Belen Sand & Gravel Co Inc; 2008-04-11 to 2008-08-04; source msha-controller-operator-history
- **controller_controls_operator:** William T Stone → Belen Sand & Gravel Co Inc; 2008-04-11 to 2004-11-30; source msha-controller-operator-history
- **operator_operates_mine:** South Valley Development Corporation → Albert Hill; 2008-08-05 to 2011-03-19; source msha-controller-operator-history
- **controller_controls_mine:** Valley Improvement Association → Albert Hill; 2008-08-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Valley Improvement Association → South Valley Development Corporation; 2008-08-05 to 2011-03-19; source msha-controller-operator-history
- **operator_operates_mine:** Western Aggregates, LLC → Albert Hill; 2011-03-20 to 2012-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Dale W  Long et al → Albert Hill; 2011-03-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale W  Long et al → Western Aggregates, LLC; 2011-03-20 to 2012-02-28; source msha-controller-operator-history
- **operator_operates_mine:** South Valley Development Corp → Albert Hill; 2012-02-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Valley Improvement Association → South Valley Development Corp; 2012-02-29 to current/open; source msha-controller-operator-history