# Relationship history for MSHA mine 2902173

Current hierarchy: **Robert  Blair; Jaqueline  Blair; William B  Turner → Blair Turner Construction → CRUSHER #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:** William B  Turner  et al → CRUSHER #1; 1995-02-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blair Turner Construction → CRUSHER #1; 1998-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William B  Turner  et al → Blair Turner Construction; 1998-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jaqueline  Blair  et al → Blair Turner Construction; 1998-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Blair  et al → Blair Turner Construction; 1998-02-01 to current/open; source msha-controller-operator-history