# Relationship history for MSHA mine 0404270

Current hierarchy: **Peter J  Lemon → Granite Rock Company → San Benito Sand Plant**

- 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

- **controller_controls_mine:** Bruce W  Woolpert  et al → San Benito Sand Plant; 1950-01-01 to 2012-07-22; source msha-controller-operator-history
- **operator_operates_mine:** Granite Rock Company → San Benito Sand Plant; 1978-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bruce W  Woolpert  et al → Granite Rock Company; 1978-06-01 to 2012-07-22; source msha-controller-operator-history
- **controller_controls_mine:** Thomas H  Squeri et al → San Benito Sand Plant; 2012-07-23 to 2022-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Thomas H  Squeri et al → Granite Rock Company; 2012-07-23 to 2022-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Peter J  Lemon → San Benito Sand Plant; 2023-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peter J  Lemon → Granite Rock Company; 2023-01-01 to current/open; source msha-controller-operator-history