# Relationship history for MSHA mine 4201450

Current hierarchy: **Atlas Resources Inc & Dirty Devil Mining Co → Atlas-Dirty Devil Mining → Blackie Surface Mine & Prep 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Atlas-Dirty Devil Mining → Blackie Surface Mine & Prep Plant; 1978-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Atlas Resources Inc & Dirty Devil Mining Co → Blackie Surface Mine & Prep Plant; 1978-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Atlas Resources Inc & Dirty Devil Mining Co → Atlas-Dirty Devil Mining; 1978-01-01 to current/open; source msha-controller-operator-history