# Relationship history for MSHA mine 3304692

Current hierarchy: **National Lime & Stone Co. → The National Lime & Stone Company → Grove City Sand & Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** National Lime & Stone Co. → Grove City Sand & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Jones Materials → Grove City Sand & Gravel; 2012-12-18 to 2016-04-04; source msha-controller-operator-history
- **controller_controls_mine:** Dave  Jones → Grove City Sand & Gravel; 2012-12-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dave  Jones → Jones Materials; 2012-12-18 to 2016-04-04; source msha-controller-operator-history
- **operator_operates_mine:** The National Lime & Stone Company → Grove City Sand & Gravel; 2016-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** National Lime & Stone Co. → The National Lime & Stone Company; 2016-04-05 to current/open; source msha-controller-operator-history