# Relationship history for MSHA mine 1518451

Current hierarchy: **Bill  Robinson; Ron  Pfaff → Kay & Kay Contracting LLC → Bear Branch**

- 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:** Kay & Kay Contracting LLC → Bear Branch; 2001-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Robinson et al → Bear Branch; 2001-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Robinson et al → Kay & Kay Contracting LLC; 2001-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ron  Pfaff et al → Kay & Kay Contracting LLC; 2001-10-01 to current/open; source msha-controller-operator-history