# Relationship history for MSHA mine 4201847

Current hierarchy: **King Edward B → Jumbo Mining Company → Drum 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:** S J Groves & Sons Company → Drum Mine; 1978-08-01 to 1990-01-07; source msha-controller-operator-history
- **operator_operates_mine:** Western States Minerals Corp → Drum Mine; 1983-09-01 to 1988-11-14; source msha-controller-operator-history
- **controller_controls_operator:** S J Groves & Sons Company → Western States Minerals Corp; 1983-09-01 to 1988-11-14; source msha-controller-operator-history
- **operator_operates_mine:** Jumbo Mining Company → Drum Mine; 1988-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** King Edward B → Drum Mine; 1988-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** King Edward B → Jumbo Mining Company; 1988-11-15 to current/open; source msha-controller-operator-history