# Relationship history for MSHA mine 2101811

Current hierarchy: **Ken  Dehmer → Ken Dehmer Trucking & Excavating → NORMAN DEHMER EXCAVATING**

- 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:** W G Pearson Inc → NORMAN DEHMER EXCAVATING; 1950-01-01 to 1986-05-06; source msha-controller-operator-history
- **controller_controls_mine:** William G Pearson → NORMAN DEHMER EXCAVATING; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William G Pearson → W G Pearson Inc; 1950-01-01 to 1986-05-06; source msha-controller-operator-history
- **operator_operates_mine:** Norman Dehmer Excavating → NORMAN DEHMER EXCAVATING; 1986-05-07 to 1995-05-23; source msha-controller-operator-history
- **controller_controls_mine:** Norman  Dehmer  et al → NORMAN DEHMER EXCAVATING; 1986-05-07 to 1995-05-23; source msha-controller-operator-history
- **controller_controls_operator:** Norman  Dehmer  et al → Norman Dehmer Excavating; 1986-05-07 to 1995-05-23; source msha-controller-operator-history
- **operator_operates_mine:** Ken Dehmer Trucking & Excavating → NORMAN DEHMER EXCAVATING; 1995-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ken  Dehmer → NORMAN DEHMER EXCAVATING; 1995-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ken  Dehmer → Ken Dehmer Trucking & Excavating; 1995-05-24 to current/open; source msha-controller-operator-history