# Relationship history for MSHA mine 3900910

Current hierarchy: **Walter  Brownlee → Brownlee Construction Company → Morehouse Pit And Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Mc Laughlin Sand & Gravel Company → Morehouse Pit And Plant; 1950-01-01 to 1978-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Mc Laughlin & Schulz Inc → Morehouse Pit And Plant; 1950-01-01 to 1978-04-19; source msha-controller-operator-history
- **controller_controls_operator:** Mc Laughlin & Schulz Inc → Mc Laughlin Sand & Gravel Company; 1950-01-01 to 1978-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Walter  Brownlee → Morehouse Pit And Plant; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Brownlee Construction Company → Morehouse Pit And Plant; 1978-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walter  Brownlee → Brownlee Construction Company; 1978-04-20 to current/open; source msha-controller-operator-history