# Relationship history for MSHA mine 3401693

Current hierarchy: **Hanson PLC → Hanson Aggregates Central Inc → TEXOMA SAND & GRAVEL**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Stringfellow & Sons Inc → TEXOMA SAND & GRAVEL; 1989-09-01 to 1996-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Curtis  Stringfellow et al → TEXOMA SAND & GRAVEL; 1989-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Curtis  Stringfellow et al → Stringfellow & Sons Inc; 1989-09-01 to 1996-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Joel  Stringfellow et al → Stringfellow & Sons Inc; 1989-09-01 to 1996-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Texoma Sand & Gravel Inc → TEXOMA SAND & GRAVEL; 1996-11-01 to 1998-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Gerald  Frey → TEXOMA SAND & GRAVEL; 1996-11-01 to 1998-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Gerald  Frey → Texoma Sand & Gravel Inc; 1996-11-01 to 1998-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Texoma Sand & Gravel Inc → TEXOMA SAND & GRAVEL; 1998-12-01 to 2000-08-03; source msha-controller-operator-history
- **controller_controls_mine:** Pioneer International Ltd → TEXOMA SAND & GRAVEL; 1998-12-01 to 2000-08-03; source msha-controller-operator-history
- **controller_controls_operator:** Pioneer International Ltd → Texoma Sand & Gravel Inc; 1998-12-01 to 2000-08-03; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates Central Inc → TEXOMA SAND & GRAVEL; 2000-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → TEXOMA SAND & GRAVEL; 2000-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates Central Inc; 2000-08-04 to current/open; source msha-controller-operator-history