# Relationship history for MSHA mine 1901134

Current hierarchy: **William  Porcella → WPC Portable Crushing → Portable Plant #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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** WPC Portable Crushing Inc → Portable Plant #1; 2004-04-19 to 2014-02-03; source msha-controller-operator-history
- **controller_controls_mine:** Danna J  Porcella → Portable Plant #1; 2004-04-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Danna J  Porcella → WPC Portable Crushing Inc; 2004-04-19 to 2014-02-03; source msha-controller-operator-history
- **operator_operates_mine:** WPC Portable Crushing → Portable Plant #1; 2014-02-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William  Porcella → Portable Plant #1; 2014-02-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William  Porcella → WPC Portable Crushing; 2014-02-04 to current/open; source msha-controller-operator-history