# Relationship history for MSHA mine 4103270

Current hierarchy: **White Richard & Edward Taylor → Northwest Sand & Gravel Ltd → Northwest Pit**

- 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:** Northwest Sand & Gravel Limited → Northwest Pit; 1984-11-01 to 1986-01-27; source msha-controller-operator-history
- **controller_controls_mine:** Carroll James W & B W Hill → Northwest Pit; 1984-11-01 to 1986-01-27; source msha-controller-operator-history
- **controller_controls_operator:** Carroll James W & B W Hill → Northwest Sand & Gravel Limited; 1984-11-01 to 1986-01-27; source msha-controller-operator-history
- **operator_operates_mine:** Northwest Sand & Gravel Ltd → Northwest Pit; 1986-01-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** White Richard & Edward Taylor → Northwest Pit; 1986-01-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** White Richard & Edward Taylor → Northwest Sand & Gravel Ltd; 1986-01-28 to current/open; source msha-controller-operator-history