# Relationship history for MSHA mine 1500137

Current hierarchy: **Steve  Lawson; Adam  Lawson → Walker Construction & Materials, LLC → Powell Stone**

- 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:** The Walker Company Of Kentucky, Inc. → Powell Stone; 1950-01-01 to 2019-10-24; source msha-controller-operator-history
- **controller_controls_mine:** Arthur E  Walker Jr → Powell Stone; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Arthur E  Walker Jr → The Walker Company Of Kentucky, Inc.; 1950-01-01 to 2019-10-24; source msha-controller-operator-history
- **controller_controls_mine:** Adam  Lawson et al → Powell Stone; 2019-10-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Walker Construction & Materials, LLC → Powell Stone; 2019-10-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Adam  Lawson et al → Walker Construction & Materials, LLC; 2019-10-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Lawson et al → Walker Construction & Materials, LLC; 2019-10-25 to current/open; source msha-controller-operator-history