# Relationship history for MSHA mine 1401027

Current hierarchy: **Don L  Knop; Daniel J  Knop → Knop Sand Co Inc → Knop Sand Co Inc**

- 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:** Tinkel Sand & Gravel Company → Knop Sand Co Inc; 1950-01-01 to 1978-03-28; source msha-controller-operator-history
- **controller_controls_mine:** Tinkel Sand & Gravel Company → Knop Sand Co Inc; 1950-01-01 to 1978-03-28; source msha-controller-operator-history
- **controller_controls_operator:** Tinkel Sand & Gravel Company → Tinkel Sand & Gravel Company; 1950-01-01 to 1978-03-28; source msha-controller-operator-history
- **operator_operates_mine:** Knop Sand Co Inc → Knop Sand Co Inc; 1978-03-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Daniel J  Knop et al → Knop Sand Co Inc; 1978-03-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Daniel J  Knop et al → Knop Sand Co Inc; 1978-03-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don L  Knop et al → Knop Sand Co Inc; 1978-03-29 to current/open; source msha-controller-operator-history