# Relationship history for MSHA mine 0505015

Current hierarchy: **Noco Gravel and Sand → Mill Iron Mining → Portable Crusher #1**

- 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:** Mill Iron Mining → Portable Crusher #1; 2013-04-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Doug D  Derr → Portable Crusher #1; 2013-04-25 to 2016-01-14; source msha-controller-operator-history
- **controller_controls_operator:** Doug D  Derr → Mill Iron Mining; 2013-04-25 to 2016-01-14; source msha-controller-operator-history
- **controller_controls_mine:** Global Recovery One et al → Portable Crusher #1; 2016-01-15 to 2023-10-17; source msha-controller-operator-history
- **controller_controls_operator:** Global Recovery One et al → Mill Iron Mining; 2016-01-15 to 2023-10-17; source msha-controller-operator-history
- **controller_controls_mine:** Noco Gravel and Sand → Portable Crusher #1; 2023-10-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Noco Gravel and Sand → Mill Iron Mining; 2023-10-18 to current/open; source msha-controller-operator-history