# Relationship history for MSHA mine 0202351

Current hierarchy: **Granite Construction Inc → Granite Construction Company → Portable #2**

- 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:** Granite Construction Inc → Portable #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sierra Ready Mix & Materials Company → Portable #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sierra Ready Mix & Materials → Portable #2; 1986-12-01 to 1989-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Sierra Ready Mix & Materials Company → Sierra Ready Mix & Materials; 1986-12-01 to 1989-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Clyde E  Davis → Portable #2; 1989-06-01 to 1994-07-07; source msha-controller-operator-history
- **operator_operates_mine:** Desert Concrete Company → Portable #2; 1989-10-01 to 1992-04-19; source msha-controller-operator-history
- **controller_controls_operator:** Clyde E  Davis → Desert Concrete Company; 1989-10-01 to 1992-04-19; source msha-controller-operator-history
- **operator_operates_mine:** Granite Construction Company → Portable #2; 1992-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Granite Construction Inc → Granite Construction Company; 1992-04-20 to current/open; source msha-controller-operator-history