# Relationship history for MSHA mine 3002862

Current hierarchy: **Langtry John S → J S L Gravel Inc → LANGBROOK 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** J S L Gravel Inc → LANGBROOK PIT; 1988-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Langtry John S → LANGBROOK PIT; 1988-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Langtry John S → J S L Gravel Inc; 1988-09-01 to current/open; source msha-controller-operator-history