# Relationship history for MSHA mine 2602322

Current hierarchy: **Taiheiyo Cement Corp → Calportland → Construx Aggregates**

- 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:** Cyrus W  Spurlino → Construx Aggregates; 1990-02-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Taiheiyo Cement Corp → Construx Aggregates; 1990-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Construx Excavators → Construx Aggregates; 1997-08-01 to 1998-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Edward  Smith  et al → Construx Aggregates; 1997-08-01 to 1998-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Edward  Smith  et al → Construx Excavators; 1997-08-01 to 1998-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Silver State Materials Corp → Construx Aggregates; 1998-04-01 to 2006-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Cyrus W  Spurlino → Silver State Materials Corp; 1998-04-01 to 2006-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Silver State Materials → Construx Aggregates; 2006-06-01 to 2008-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Audax Group et al → Construx Aggregates; 2006-06-01 to 2008-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Audax Group et al → Silver State Materials; 2006-06-01 to 2008-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Taiheiyo Cement Corp → Construx Aggregates; 2008-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Taiheiyo Cement Corp → Silver State Materials; 2008-05-01 to 2008-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Calportland → Construx Aggregates; 2009-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Taiheiyo Cement Corp → Calportland; 2009-01-01 to current/open; source msha-controller-operator-history