# Relationship history for MSHA mine 5001977

Current hierarchy: **Mark W  Sanford → Northland Fuels and Energy → Northland Coal Screening 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:** Mark W  Sanford et al → Northland Coal Screening Plant; 2007-05-14 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Northland Fuels and Energy → Northland Coal Screening Plant; 2012-05-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark W  Sanford et al → Northland Fuels and Energy; 2012-05-09 to current/open; source msha-controller-operator-history