# Relationship history for MSHA mine 3304676

Current hierarchy: **Barton S  Holl; Richard H  Brandt → The Logan Clay Products Company → Web Summit**

- 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

- **controller_controls_mine:** Barton S  Holl et al → Web Summit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** The Logan Clay Products Company → Web Summit; 2011-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barton S  Holl et al → The Logan Clay Products Company; 2011-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard H  Brandt et al → The Logan Clay Products Company; 2011-09-01 to current/open; source msha-controller-operator-history