# Relationship history for MSHA mine 4502518

Current hierarchy: **Natalie  Karnas; John  Karnas → Willapa Rock & Supply, Inc. → Portable 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:** Harbor Rock Inc → Portable 1; 1950-01-01 to 2018-10-16; source msha-controller-operator-history
- **controller_controls_mine:** Harbor Rock Inc → Portable 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harbor Rock Inc → Harbor Rock Inc; 1950-01-01 to 2018-10-16; source msha-controller-operator-history
- **operator_operates_mine:** Willapa Rock & Supply, Inc. → Portable 1; 2018-10-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Karnas et al → Portable 1; 2018-10-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Karnas et al → Willapa Rock & Supply, Inc.; 2018-10-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Natalie  Karnas et al → Willapa Rock & Supply, Inc.; 2018-10-17 to current/open; source msha-controller-operator-history