# Relationship history for MSHA mine 2500949

Current hierarchy: **Frank  Vollmer → Bluff Aggregate LLC → Bluff Aggregate LLC**

- 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:** Drevo Inc → Bluff Aggregate LLC; 1979-01-01 to 1984-07-15; source msha-controller-operator-history
- **controller_controls_mine:** James L  Coen → Bluff Aggregate LLC; 1979-01-01 to 1984-07-15; source msha-controller-operator-history
- **controller_controls_operator:** James L  Coen → Drevo Inc; 1979-01-01 to 1984-07-15; source msha-controller-operator-history
- **operator_operates_mine:** Bluff Gravel Co → Bluff Aggregate LLC; 1984-07-16 to 2023-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Ted J  Minarick  et al → Bluff Aggregate LLC; 1984-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ted J  Minarick  et al → Bluff Gravel Co; 1984-07-16 to 2023-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Steve J  Minarick  et al → Bluff Gravel Co; 1984-07-16 to 2023-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Bluff Aggregate LLC → Bluff Aggregate LLC; 2023-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Frank  Vollmer → Bluff Aggregate LLC; 2023-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frank  Vollmer → Bluff Aggregate LLC; 2023-05-01 to current/open; source msha-controller-operator-history