# Relationship history for MSHA mine 0503802

Current hierarchy: **Holcim Ltd → Lafarge West Incorporated → NORTHERN PORTABLE PLANT #22**

- 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:** Roaring Fork Sand & Gravel → NORTHERN PORTABLE PLANT #22; 1982-08-01 to 1985-09-04; source msha-controller-operator-history
- **controller_controls_mine:** Gmco Corp et al → NORTHERN PORTABLE PLANT #22; 1982-08-01 to 1985-09-04; source msha-controller-operator-history
- **controller_controls_operator:** Gmco Corp et al → Roaring Fork Sand & Gravel; 1982-08-01 to 1985-09-04; source msha-controller-operator-history
- **operator_operates_mine:** Roaring Fork Aggregates Inc → NORTHERN PORTABLE PLANT #22; 1985-09-05 to 2001-06-21; source msha-controller-operator-history
- **controller_controls_mine:** John C  Martin et al → NORTHERN PORTABLE PLANT #22; 1985-09-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John C  Martin et al → Roaring Fork Aggregates Inc; 1985-09-05 to 2001-06-21; source msha-controller-operator-history
- **controller_controls_operator:** Richard K  Stephenson et al → Roaring Fork Aggregates Inc; 1985-09-05 to 2001-06-21; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → NORTHERN PORTABLE PLANT #22; 1998-02-11 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western Mobile Northern Inc → NORTHERN PORTABLE PLANT #22; 2001-06-22 to 2002-01-30; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Western Mobile Northern Inc; 2001-06-22 to 2002-01-30; source msha-controller-operator-history
- **operator_operates_mine:** Lafarge West Incorporated → NORTHERN PORTABLE PLANT #22; 2002-01-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → NORTHERN PORTABLE PLANT #22; 2002-01-31 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge West Incorporated; 2002-01-31 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → NORTHERN PORTABLE PLANT #22; 2015-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Lafarge West Incorporated; 2015-07-10 to current/open; source msha-controller-operator-history