# Relationship history for MSHA mine 3607880

Current hierarchy: **Spencer J Svonavec → Simkol Corp. → Condor 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:** Donald  Simpson → Condor Mine; 1984-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Simpson Coal Company → Condor Mine; 1987-04-01 to 2013-01-10; source msha-controller-operator-history
- **controller_controls_operator:** Donald  Simpson → Simpson Coal Company; 1987-04-01 to 2013-01-10; source msha-controller-operator-history
- **operator_operates_mine:** Simkol Corp. → Condor Mine; 2013-01-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Donald  Simpson → Condor Mine; 2013-01-11 to 2022-03-28; source msha-controller-operator-history
- **controller_controls_operator:** Donald  Simpson → Simkol Corp.; 2013-01-11 to 2022-03-28; source msha-controller-operator-history
- **controller_controls_mine:** Spencer J Svonavec → Condor Mine; 2022-03-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Spencer J Svonavec → Simkol Corp.; 2022-03-29 to current/open; source msha-controller-operator-history