# Relationship history for MSHA mine 1516383

Current hierarchy: **Salyer Billy R → Coby Inc → #1 Surface**

- 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:** Salyer Billy R → #1 Surface; 1981-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Coby Inc → #1 Surface; 1988-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Salyer Billy R → Coby Inc; 1988-05-01 to current/open; source msha-controller-operator-history