# Relationship history for MSHA mine 0103576

Current hierarchy: **Darrin K  Isbell → North Alabama Materials, Inc → Laceys Springs 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

- **controller_controls_mine:** Brian K  McCord → Laceys Springs Quarry; 2018-01-31 to 2020-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Darrin K  Isbell → Laceys Springs Quarry; 2020-11-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** North Alabama Materials, Inc → Laceys Springs Quarry; 2023-01-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brian K  McCord → North Alabama Materials, Inc; 2023-01-04 to 2020-11-29; source msha-controller-operator-history
- **controller_controls_operator:** Darrin K  Isbell → North Alabama Materials, Inc; 2023-01-04 to current/open; source msha-controller-operator-history