# Relationship history for MSHA mine 1302191

Current hierarchy: **Dale  Tiefenthaler → Tiefenthaler Ag Lime Inc. → Portable Sand Plant #2**

- 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

- **controller_controls_mine:** Dale  Tiefenthaler et al → Portable Sand Plant #2; 1985-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tiefenthaler Ag Lime Inc. → Portable Sand Plant #2; 1992-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale  Tiefenthaler et al → Tiefenthaler Ag Lime Inc.; 1992-11-01 to current/open; source msha-controller-operator-history