# Relationship history for MSHA mine 2601978

Current hierarchy: **Helms Robert L Construction & Development Co → Lost Dutchman Construction Inc → Weepah Mine**

- 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:** Helms Robert L Construction & Development Co → Weepah Mine; 1986-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lost Dutchman Construction Inc → Weepah Mine; 1986-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Helms Robert L Construction & Development Co → Lost Dutchman Construction Inc; 1986-09-01 to current/open; source msha-controller-operator-history