# Relationship history for MSHA mine 2103624

Current hierarchy: **Gary A  Leitzen → Leitzen Sand & Gravel → Greybull Pit**

- 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:** Robert A  Hemker et al → Greybull Pit; 2001-04-01 to 2016-06-26; source msha-controller-operator-history
- **operator_operates_mine:** Brannt Valley Excavating → Greybull Pit; 2008-06-09 to 2013-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Robert A  Hemker et al → Brannt Valley Excavating; 2008-06-09 to 2013-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Travis R  Hemker et al → Brannt Valley Excavating; 2008-06-09 to 2013-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Leitzen Sand & Gravel → Greybull Pit; 2014-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gary A  Leitzen et al → Greybull Pit; 2014-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary A  Leitzen et al → Leitzen Sand & Gravel; 2014-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Travis R Hemker → Greybull Pit; 2016-06-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Travis R Hemker → Brannt Valley Excavating; 2016-06-27 to 2013-12-31; source msha-controller-operator-history