# Relationship history for MSHA mine 2901235

Current hierarchy: **John  Sanchez → Sanchez Trucking → SANCHEZ 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:** Los Lunas Sand & Gravel Company → SANCHEZ SAND & GRAVEL; 1978-01-15 to 1978-09-15; source msha-controller-operator-history
- **controller_controls_mine:** Los Lunas Sand & Gravel Company → SANCHEZ SAND & GRAVEL; 1978-01-15 to 1978-09-15; source msha-controller-operator-history
- **controller_controls_operator:** Los Lunas Sand & Gravel Company → Los Lunas Sand & Gravel Company; 1978-01-15 to 1978-09-15; source msha-controller-operator-history
- **operator_operates_mine:** Nitty Gritty Enterprises → SANCHEZ SAND & GRAVEL; 1978-09-16 to 1993-04-04; source msha-controller-operator-history
- **controller_controls_mine:** Washburn Brice P → SANCHEZ SAND & GRAVEL; 1978-09-16 to 1993-04-04; source msha-controller-operator-history
- **controller_controls_operator:** Washburn Brice P → Nitty Gritty Enterprises; 1978-09-16 to 1993-04-04; source msha-controller-operator-history
- **operator_operates_mine:** Sanchez Trucking → SANCHEZ SAND & GRAVEL; 1993-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Sanchez → SANCHEZ SAND & GRAVEL; 1993-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Sanchez → Sanchez Trucking; 1993-04-05 to current/open; source msha-controller-operator-history