# Relationship history for MSHA mine 2102666

Current hierarchy: **Keith R  Comstock → Comstock Trucking → Heinz Quarry**

- 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:** L J'S Sand & Gravel Inc → Heinz Quarry; 1978-03-09 to 1981-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Lyle E  Johnson → Heinz Quarry; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lyle E  Johnson → L J'S Sand & Gravel Inc; 1978-03-09 to 1981-11-04; source msha-controller-operator-history
- **operator_operates_mine:** Comstock Trucking → Heinz Quarry; 1981-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Keith R  Comstock → Heinz Quarry; 1981-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith R  Comstock → Comstock Trucking; 1981-11-05 to current/open; source msha-controller-operator-history