# Relationship history for MSHA mine 3900670

Current hierarchy: **Jeffrey L  Cullum → Mineral Technology Corporation → Dakota Quartz Plant**

- 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:** Pacer Corp → Dakota Quartz Plant; 1950-01-01 to 1987-01-06; source msha-controller-operator-history
- **controller_controls_mine:** Julie  Oswald et al → Dakota Quartz Plant; 1950-01-01 to 2016-02-18; source msha-controller-operator-history
- **controller_controls_operator:** Julie  Oswald et al → Pacer Corp; 1950-01-01 to 1987-01-06; source msha-controller-operator-history
- **operator_operates_mine:** Mineral Technology Corporation → Dakota Quartz Plant; 1987-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jeffrey L  Cullum → Dakota Quartz Plant; 1987-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeffrey L  Cullum → Mineral Technology Corporation; 1987-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Burns et al → Dakota Quartz Plant; 2016-02-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Burns et al → Pacer Corp; 2016-02-19 to 1987-01-06; source msha-controller-operator-history