# Relationship history for MSHA mine 1302120

Current hierarchy: **Dale  Tiefenthaler → Tiefenthaler Ag-Lime Inc → Portable Sand Plant #1**

- 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:** Tiefenthaler Ag-Lime Inc → Portable Sand Plant #1; 1985-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dale  Tiefenthaler et al → Portable Sand Plant #1; 1985-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale  Tiefenthaler et al → Tiefenthaler Ag-Lime Inc; 1985-07-01 to current/open; source msha-controller-operator-history