# Relationship history for MSHA mine 3101992

Current hierarchy: **David  McEvers → Hancock Sand → Hancock Sand**

- 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:** Frances B  Hancock → Hancock Sand; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hancock Sand Company → Hancock Sand; 1986-03-01 to 2006-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Frances B  Hancock → Hancock Sand Company; 1986-03-01 to 2006-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Hancock Sand → Hancock Sand; 2006-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David  McEvers → Hancock Sand; 2006-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  McEvers → Hancock Sand; 2006-02-01 to current/open; source msha-controller-operator-history