# Relationship history for MSHA mine 3500723

Current hierarchy: **MDU Resources Group Inc → Tri City Ready Mix → SMITH BAR**

- 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:** Tri City Redy Mix Inc → SMITH BAR; 1950-01-01 to 1981-01-27; source msha-controller-operator-history
- **controller_controls_mine:** John W  Doud → SMITH BAR; 1950-01-01 to 1981-01-27; source msha-controller-operator-history
- **controller_controls_operator:** John W  Doud → Tri City Redy Mix Inc; 1950-01-01 to 1981-01-27; source msha-controller-operator-history
- **operator_operates_mine:** Tri City Ready Mix Inc → SMITH BAR; 1981-01-28 to 2000-08-28; source msha-controller-operator-history
- **controller_controls_mine:** S J  Loosley → SMITH BAR; 1981-01-28 to 2000-08-28; source msha-controller-operator-history
- **controller_controls_operator:** S J  Loosley → Tri City Ready Mix Inc; 1981-01-28 to 2000-08-28; source msha-controller-operator-history
- **operator_operates_mine:** Tri City Ready Mix → SMITH BAR; 2000-08-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → SMITH BAR; 2000-08-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Tri City Ready Mix; 2000-08-29 to current/open; source msha-controller-operator-history