# Relationship history for MSHA mine 2602213

Current hierarchy: **Keith  Jones → Small Mine Development → Fortitude (U/G)**

- 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:** Ronald W  Guill → Fortitude (U/G); 1988-04-01 to 2011-01-27; source msha-controller-operator-history
- **operator_operates_mine:** Small Mine Development → Fortitude (U/G); 1992-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald W  Guill → Small Mine Development; 1992-10-01 to 2011-01-27; source msha-controller-operator-history
- **controller_controls_mine:** Keith  Jones → Fortitude (U/G); 2011-01-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith  Jones → Small Mine Development; 2011-01-28 to current/open; source msha-controller-operator-history