# Relationship history for MSHA mine 1601556

Current hierarchy: **Ken  Myers → Tusk Subsea Services → Tusk Subsea**

- 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:** Tusk Subsea Services → Tusk Subsea; 2015-09-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ken  Myers et al → Tusk Subsea; 2015-09-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ken  Myers et al → Tusk Subsea Services; 2015-09-21 to current/open; source msha-controller-operator-history