# Relationship history for MSHA mine 1900558

Current hierarchy: **Francis A  Will → A A Will Materials Corp → Portable Plants**

- 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:** Lakeville Sand & Gravel Corp → Portable Plants; 1950-01-01 to 1982-12-06; source msha-controller-operator-history
- **controller_controls_mine:** Eveline A  Kelleher et al → Portable Plants; 1950-01-01 to 1982-12-06; source msha-controller-operator-history
- **controller_controls_operator:** Eveline A  Kelleher et al → Lakeville Sand & Gravel Corp; 1950-01-01 to 1982-12-06; source msha-controller-operator-history
- **controller_controls_mine:** Francis A  Will et al → Portable Plants; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** A A Will Materials Corp → Portable Plants; 1982-12-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Francis A  Will et al → A A Will Materials Corp; 1982-12-07 to current/open; source msha-controller-operator-history