# Relationship history for MSHA mine 2800958

Current hierarchy: **Buskirk Bertha → R H Materials Company Inc → R H Materials Company Incorporated**

- 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:** K P & B Company → R H Materials Company Incorporated; 1979-12-01 to 1984-11-18; source msha-controller-operator-history
- **controller_controls_mine:** Kimbrough John → R H Materials Company Incorporated; 1979-12-01 to 1984-11-18; source msha-controller-operator-history
- **controller_controls_operator:** Kimbrough John → K P & B Company; 1979-12-01 to 1984-11-18; source msha-controller-operator-history
- **operator_operates_mine:** R H Materials Company Inc → R H Materials Company Incorporated; 1984-11-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Buskirk Bertha → R H Materials Company Incorporated; 1984-11-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Buskirk Bertha → R H Materials Company Inc; 1984-11-19 to current/open; source msha-controller-operator-history