# Relationship history for MSHA mine 3003540

Current hierarchy: **Mark A  Colf → Mark Colf Excavation Contracting Inc. → Mark Colf Excavation Contracting 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Mark Colf Excavation Contracting Inc. → Mark Colf Excavation Contracting Inc.; 2006-04-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark A  Colf → Mark Colf Excavation Contracting Inc.; 2006-04-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark A  Colf → Mark Colf Excavation Contracting Inc.; 2006-04-25 to current/open; source msha-controller-operator-history