# Relationship history for MSHA mine 3608372

Current hierarchy: **Tracy E  Keeney → KBK Corp → KBK Quarry**

- 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:** Walter Flagstone Company → KBK Quarry; 1992-12-01 to 2006-10-25; source msha-controller-operator-history
- **controller_controls_mine:** William W  Walter Sr → KBK Quarry; 1992-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William W  Walter Sr → Walter Flagstone Company; 1992-12-01 to 2006-10-25; source msha-controller-operator-history
- **operator_operates_mine:** M & M Flagstone → KBK Quarry; 2006-10-26 to 2009-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Melvin  Heeman → KBK Quarry; 2006-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Melvin  Heeman → M & M Flagstone; 2006-10-26 to 2009-04-19; source msha-controller-operator-history
- **operator_operates_mine:** KBK Corp → KBK Quarry; 2009-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tracy E  Keeney → KBK Quarry; 2009-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tracy E  Keeney → KBK Corp; 2009-04-20 to current/open; source msha-controller-operator-history