# Relationship history for MSHA mine 1002021

Current hierarchy: **Summit Materials LLC → Kilgore Companies LLC dba Walker Sand and Gravel → Walker Sand & Gravel**

- 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:** Harold  Elam → Walker Sand & Gravel; 1950-01-01 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Larry D Anderson et al → Walker Sand & Gravel; 1987-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Anderson Asphalt Paving → Walker Sand & Gravel; 2002-03-11 to 2011-02-14; source msha-controller-operator-history
- **controller_controls_operator:** Larry D Anderson et al → Anderson Asphalt Paving; 2002-03-11 to 2011-02-14; source msha-controller-operator-history
- **operator_operates_mine:** Anderson Asphalt Paving, Inc. → Walker Sand & Gravel; 2011-02-15 to 2023-03-08; source msha-controller-operator-history
- **controller_controls_mine:** Larry D Anderson et al → Walker Sand & Gravel; 2011-02-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry D Anderson et al → Anderson Asphalt Paving, Inc.; 2011-02-15 to 2023-03-08; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Walker Sand & Gravel; 2011-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kilgore Companies LLC dba Walker Sand and Gravel → Walker Sand & Gravel; 2023-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold  Elam → Kilgore Companies LLC dba Walker Sand and Gravel; 2023-03-09 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → Kilgore Companies LLC dba Walker Sand and Gravel; 2023-03-09 to current/open; source msha-controller-operator-history