# Relationship history for MSHA mine 1700840

Current hierarchy: **Ralph J  Sawyer; Thomas H  Learned → Route 26 Excavation and Sales, Inc. → Route 26 Excavation and Sales, Inc.**

- 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:** Route 26 Excavation and Sales, Inc. → Route 26 Excavation and Sales, Inc.; 2008-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ralph J  Sawyer et al → Route 26 Excavation and Sales, Inc.; 2008-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ralph J  Sawyer et al → Route 26 Excavation and Sales, Inc.; 2008-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas H  Learned et al → Route 26 Excavation and Sales, Inc.; 2008-08-04 to current/open; source msha-controller-operator-history