# Relationship history for MSHA mine 2302252

Current hierarchy: **Donald L  Webb Jr; Dianna K  Johnston → Arch Johnston Company, Inc. → Ridgeview 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

- **controller_controls_mine:** Arch  Johnston → Ridgeview Quarry; 1950-01-01 to 2015-07-18; source msha-controller-operator-history
- **operator_operates_mine:** Arch Johnston Company, Inc. → Ridgeview Quarry; 2001-07-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Arch  Johnston → Arch Johnston Company, Inc.; 2001-07-20 to 2015-07-18; source msha-controller-operator-history
- **controller_controls_mine:** Dianna K  Johnston et al → Ridgeview Quarry; 2015-07-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dianna K  Johnston et al → Arch Johnston Company, Inc.; 2015-07-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald L  Webb Jr et al → Arch Johnston Company, Inc.; 2015-07-19 to current/open; source msha-controller-operator-history