# Relationship history for MSHA mine 3607912

Current hierarchy: **Decker Kenneth → Kenneth Decker → Preston 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:** Nff → Preston Quarry; 1987-09-01 to 1989-07-17; source msha-controller-operator-history
- **controller_controls_mine:** Newhart Dennis L & Frank Et Al → Preston Quarry; 1987-09-01 to 1989-07-17; source msha-controller-operator-history
- **controller_controls_operator:** Newhart Dennis L & Frank Et Al → Nff; 1987-09-01 to 1989-07-17; source msha-controller-operator-history
- **controller_controls_mine:** Decker Kenneth → Preston Quarry; 1987-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kenneth Decker → Preston Quarry; 1989-07-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Decker Kenneth → Kenneth Decker; 1989-07-18 to current/open; source msha-controller-operator-history