# Relationship history for MSHA mine 4300339

Current hierarchy: **Campbell J M → Lake Memphremagog Views Inc → Old Drown Gravel 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:** Lake Memphremagog Views Inc → Old Drown Gravel Pit; 1980-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Campbell J M → Old Drown Gravel Pit; 1980-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Campbell J M → Lake Memphremagog Views Inc; 1980-04-01 to current/open; source msha-controller-operator-history