# Relationship history for MSHA mine 4000820

Current hierarchy: **Paul  Wills; Dee  Wills Goodwin → Tri-State Sand Company → Camden**

- 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:** Tri-State Sand Company → Camden; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dee  Wills Goodwin et al → Camden; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dee  Wills Goodwin et al → Tri-State Sand Company; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul  Wills et al → Tri-State Sand Company; 1950-01-01 to current/open; source msha-controller-operator-history