# Relationship history for MSHA mine 1700665

Current hierarchy: **Mark  O'Brien → O'Brien Sand & Gravel → QUARRY RD. PIT**

- 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

- **operator_operates_mine:** O'Brien Sand & Gravel → QUARRY RD. PIT; 1999-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark  O'Brien → QUARRY RD. PIT; 1999-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  O'Brien → O'Brien Sand & Gravel; 1999-12-01 to current/open; source msha-controller-operator-history