# Relationship history for MSHA mine 4105350

Current hierarchy: **Tracy  Schieffer; Rick  Helmcamp → Helmcamp Materials, Ltd. → Christmas 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:** Helmcamp Materials, Ltd. → Christmas Quarry; 2018-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rick  Helmcamp et al → Christmas Quarry; 2018-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rick  Helmcamp et al → Helmcamp Materials, Ltd.; 2018-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tracy  Schieffer et al → Helmcamp Materials, Ltd.; 2018-03-27 to current/open; source msha-controller-operator-history