# Relationship history for MSHA mine 0504158

Current hierarchy: **Pueblo County - Co → Pueblo County Public Works → PORTABLE SCREENING & CRUSHING**

- 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:** Pueblo County Public Works → PORTABLE SCREENING & CRUSHING; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pueblo County - Co → PORTABLE SCREENING & CRUSHING; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pueblo County - Co → Pueblo County Public Works; 1986-07-01 to current/open; source msha-controller-operator-history