# Relationship history for MSHA mine 3300088

Current hierarchy: **Holcim Ltd → Lafarge North America Inc → Kelleys Island**

- 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:** Quality Quarries Inc → Kelleys Island; 1950-01-01 to 1992-09-28; source msha-controller-operator-history
- **controller_controls_mine:** Clyde  Van Enkevert → Kelleys Island; 1950-01-01 to 1992-09-28; source msha-controller-operator-history
- **controller_controls_operator:** Clyde  Van Enkevert → Quality Quarries Inc; 1950-01-01 to 1992-09-28; source msha-controller-operator-history
- **operator_operates_mine:** Kellstone Inc → Kelleys Island; 1992-09-29 to 2004-03-03; source msha-controller-operator-history
- **controller_controls_mine:** James  Palladino → Kelleys Island; 1992-09-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James  Palladino → Kellstone Inc; 1992-09-29 to 2004-03-03; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Kelleys Island; 2001-07-12 to 2015-07-09; source msha-controller-operator-history
- **operator_operates_mine:** Lafarge North America Inc → Kelleys Island; 2004-03-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge North America Inc; 2004-03-04 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Kelleys Island; 2015-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Lafarge North America Inc; 2015-07-10 to current/open; source msha-controller-operator-history