# Relationship history for MSHA mine 3901349

Current hierarchy: **Mark  Schultz → Lake Sand & Gravel Inc → Screener 5 X 10**

- 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:** Mark  Schultz → Screener 5 X 10; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lake Sand & Gravel Inc → Screener 5 X 10; 1986-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Schultz → Lake Sand & Gravel Inc; 1986-02-01 to current/open; source msha-controller-operator-history