# Relationship history for MSHA mine 1901290

Current hierarchy: **John R Mercier → Northeast Sand & Gravel Products LLC → Northeast Sand & Gravel Products LLC**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Northeast Sand & Gravel Products LLC → Northeast Sand & Gravel Products LLC; 2020-06-22 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John R Mercier → Northeast Sand & Gravel Products LLC; 2020-06-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John R Mercier → Northeast Sand & Gravel Products LLC; 2020-06-22 to current/open; source msha-controller-operator-history