# Relationship history for MSHA mine 0404778

Current hierarchy: **Terry  Klenske → Dalton Trucking Inc → Portable Operation**

- 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

- **controller_controls_mine:** Hanson PLC → Portable Operation; 1979-12-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Riverside Cement Company → Portable Operation; 1985-06-01 to 1992-01-19; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Riverside Cement Company; 1985-06-01 to 1992-01-19; source msha-controller-operator-history
- **operator_operates_mine:** Dalton Trucking Inc → Portable Operation; 1992-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Terry  Klenske → Portable Operation; 1992-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Terry  Klenske → Dalton Trucking Inc; 1992-01-20 to current/open; source msha-controller-operator-history