# Relationship history for MSHA mine 1518084

Current hierarchy: **Vicki  Salyer → Elkhorn Crystal Inc → No 21**

- 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:** Vicki  Salyer et al → No 21; 1994-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** George P  Givens → No 21; 1995-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bernthaler Inc → No 21; 1998-08-01 to 1998-08-11; source msha-controller-operator-history
- **controller_controls_operator:** George P  Givens → Bernthaler Inc; 1998-08-01 to 1998-08-11; source msha-controller-operator-history
- **operator_operates_mine:** Elkhorn Crystal Inc → No 21; 1998-08-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vicki  Salyer et al → Elkhorn Crystal Inc; 1998-08-12 to current/open; source msha-controller-operator-history