# Relationship history for MSHA mine 0900986

Current hierarchy: **Harry E  Lambert; Ray P  Lambert Jr → Lambert Sand & Gravel Company Incorporated → Lambert Pit #10**

- 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:** Lambert Sand & Gravel Company Inc → Lambert Pit #10; 1986-07-01 to 1993-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Harry E  Lambert et al → Lambert Pit #10; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harry E  Lambert et al → Lambert Sand & Gravel Company Inc; 1986-07-01 to 1993-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Ray P  Lambert Jr et al → Lambert Sand & Gravel Company Inc; 1986-07-01 to 1993-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Henry  Hamilton → Lambert Pit #10; 1988-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hamilton Construction Inc → Lambert Pit #10; 1993-06-01 to 1997-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Henry  Hamilton → Hamilton Construction Inc; 1993-06-01 to 1997-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Lambert Sand & Gravel Company Incorporated → Lambert Pit #10; 1997-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ray P  Lambert Jr et al → Lambert Sand & Gravel Company Incorporated; 1997-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harry E  Lambert et al → Lambert Sand & Gravel Company Incorporated; 1997-10-01 to current/open; source msha-controller-operator-history