# Relationship history for MSHA mine 0900076

Current hierarchy: **David A  Giannoni → North Ridge Granite Quarries Inc → North Ridge 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Worley Brothers Granite Company Inc → North Ridge Quarry; 1950-01-01 to 1999-10-11; source msha-controller-operator-history
- **controller_controls_mine:** Speed  Worley → North Ridge Quarry; 1950-01-01 to 1999-10-11; source msha-controller-operator-history
- **controller_controls_operator:** Speed  Worley → Worley Brothers Granite Company Inc; 1950-01-01 to 1999-10-11; source msha-controller-operator-history
- **operator_operates_mine:** Skyway Granite Company Inc → North Ridge Quarry; 1999-10-12 to 2001-02-26; source msha-controller-operator-history
- **controller_controls_mine:** Kenneth S  Worley → North Ridge Quarry; 1999-10-12 to 2001-02-26; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth S  Worley → Skyway Granite Company Inc; 1999-10-12 to 2001-02-26; source msha-controller-operator-history
- **operator_operates_mine:** Worley Blue Quarry → North Ridge Quarry; 2001-02-27 to 2007-03-27; source msha-controller-operator-history
- **controller_controls_mine:** Eric  Higginbotham → North Ridge Quarry; 2001-02-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eric  Higginbotham → Worley Blue Quarry; 2001-02-27 to 2007-03-27; source msha-controller-operator-history
- **operator_operates_mine:** North Ridge Granite Quarries Inc → North Ridge Quarry; 2007-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David A  Giannoni → North Ridge Quarry; 2007-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David A  Giannoni → North Ridge Granite Quarries Inc; 2007-03-28 to current/open; source msha-controller-operator-history