# Relationship history for MSHA mine 1800348

Current hierarchy: **Beverly A  Critchfield → Maryland Minerals Inc → MARYLAND MINERALS**

- 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:** Garrett Minerals Corp → MARYLAND MINERALS; 1950-01-01 to 1980-04-08; source msha-controller-operator-history
- **controller_controls_mine:** A H  Wilson → MARYLAND MINERALS; 1950-01-01 to 1980-04-08; source msha-controller-operator-history
- **controller_controls_operator:** A H  Wilson → Garrett Minerals Corp; 1950-01-01 to 1980-04-08; source msha-controller-operator-history
- **operator_operates_mine:** Maryland Minerals Inc → MARYLAND MINERALS; 1980-04-09 to 1991-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Dean M  Hottle → MARYLAND MINERALS; 1980-04-09 to 1991-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Dean M  Hottle → Maryland Minerals Inc; 1980-04-09 to 1991-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Maryland Minerals Inc → MARYLAND MINERALS; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Beverly A  Critchfield et al → MARYLAND MINERALS; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Beverly A  Critchfield et al → Maryland Minerals Inc; 1991-07-01 to current/open; source msha-controller-operator-history