# Relationship history for MSHA mine 2902150

Current hierarchy: **Karl  Schneider → Schneider Welding → KEYSTONE #1**

- 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:** Schneider Welding → KEYSTONE #1; 1995-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Karl  Schneider → KEYSTONE #1; 1995-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Karl  Schneider → Schneider Welding; 1995-08-01 to current/open; source msha-controller-operator-history