# Relationship history for MSHA mine 2602543

Current hierarchy: **Barbara  Spurgeon → Black Mountain Industrial Minerals LLC → Ivory Mine**

- 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

- **controller_controls_mine:** Barbara  Spurgeon et al → Ivory Mine; 2002-06-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Industrial Minerals & Technology, LLC → Ivory Mine; 2004-09-15 to 2007-05-02; source msha-controller-operator-history
- **controller_controls_mine:** Dennis M  Anderson → Ivory Mine; 2004-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dennis M  Anderson → Industrial Minerals & Technology, LLC; 2004-09-15 to 2007-05-02; source msha-controller-operator-history
- **operator_operates_mine:** Black Mountain Industrial Minerals LLC → Ivory Mine; 2007-05-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barbara  Spurgeon et al → Black Mountain Industrial Minerals LLC; 2007-05-03 to current/open; source msha-controller-operator-history