# Relationship history for MSHA mine 3502548

Current hierarchy: **Lloyd S  Hockema → Lloyd S Hockema Inc → Swisshome Rock Quarry**

- 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:** Hardrock Quarry Inc → Swisshome Rock Quarry; 1950-01-01 to 1985-02-03; source msha-controller-operator-history
- **controller_controls_mine:** Arthur V  Miville Jr → Swisshome Rock Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Arthur V  Miville Jr → Hardrock Quarry Inc; 1950-01-01 to 1985-02-03; source msha-controller-operator-history
- **operator_operates_mine:** Ferguson Logging Company → Swisshome Rock Quarry; 1985-02-04 to 1987-06-30; source msha-controller-operator-history
- **controller_controls_mine:** R Gary  Ferguson → Swisshome Rock Quarry; 1985-02-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** R Gary  Ferguson → Ferguson Logging Company; 1985-02-04 to 1987-06-30; source msha-controller-operator-history
- **operator_operates_mine:** S2-F Corp → Swisshome Rock Quarry; 1987-07-01 to 1990-01-16; source msha-controller-operator-history
- **controller_controls_mine:** M O  Salmon Sr → Swisshome Rock Quarry; 1987-07-01 to 1994-11-13; source msha-controller-operator-history
- **controller_controls_operator:** M O  Salmon Sr → S2-F Corp; 1987-07-01 to 1990-01-16; source msha-controller-operator-history
- **operator_operates_mine:** Lloyd S Hockema Inc → Swisshome Rock Quarry; 1990-01-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lloyd S  Hockema → Swisshome Rock Quarry; 1990-01-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lloyd S  Hockema → Lloyd S Hockema Inc; 1990-01-17 to current/open; source msha-controller-operator-history