# Relationship history for MSHA mine 2103640

Current hierarchy: **Mike Dean  Scheffler → L & S Const. Corp. → Portable Secondary 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

- **controller_controls_mine:** Herb L  Scheffler → Portable Secondary Plant; 1991-06-01 to 2023-01-04; source msha-controller-operator-history
- **operator_operates_mine:** L & S Const. Corp. → Portable Secondary Plant; 2008-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Herb L  Scheffler → L & S Const. Corp.; 2008-07-30 to 2023-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Mike Dean  Scheffler → Portable Secondary Plant; 2023-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mike Dean  Scheffler → L & S Const. Corp.; 2023-01-05 to current/open; source msha-controller-operator-history