# Relationship history for MSHA mine 3608626

Current hierarchy: **Ronald J Powers; Mark  Powers → Powers Stone Inc → PORTABLE SAW #1**

- 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:** Ronald J Powers et al → PORTABLE SAW #1; 1997-03-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Powers Stone Inc → PORTABLE SAW #1; 1997-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald J Powers et al → Powers Stone Inc; 1997-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Powers et al → Powers Stone Inc; 1997-04-01 to current/open; source msha-controller-operator-history