# Relationship history for MSHA mine 4300196

Current hierarchy: **David C Camara → VT UNFADING GREEN SLATE COMPANY INC → BLISSVILLE QUARRY & MILL**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Green Mountain Slate Inc → BLISSVILLE QUARRY & MILL; 1950-01-01 to 1986-11-24; source msha-controller-operator-history
- **controller_controls_mine:** William J  Billow → BLISSVILLE QUARRY & MILL; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William J  Billow → Green Mountain Slate Inc; 1950-01-01 to 1986-11-24; source msha-controller-operator-history
- **operator_operates_mine:** Vt Unfading Green Slate Company Inc → BLISSVILLE QUARRY & MILL; 1986-11-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David C Camara et al → BLISSVILLE QUARRY & MILL; 1986-11-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David C Camara et al → Vt Unfading Green Slate Company Inc; 1986-11-25 to current/open; source msha-controller-operator-history