# Relationship history for MSHA mine 2102623

Current hierarchy: **Schulke Family Trust; Eric  Schulke; Kyle  Schulke → NORTHERN AGGREGATE INC. → PORTABLE CRUSHER**

- 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:** Davidson Construction → PORTABLE CRUSHER; 1978-03-09 to 1987-06-17; source msha-controller-operator-history
- **controller_controls_mine:** Ronald D  Davidson → PORTABLE CRUSHER; 1978-03-09 to 2025-07-15; source msha-controller-operator-history
- **controller_controls_operator:** Ronald D  Davidson → Davidson Construction; 1978-03-09 to 1987-06-17; source msha-controller-operator-history
- **operator_operates_mine:** M & J Construction → PORTABLE CRUSHER; 1987-06-18 to 2001-03-05; source msha-controller-operator-history
- **controller_controls_mine:** Myron  Olberg → PORTABLE CRUSHER; 1987-06-18 to 2013-10-20; source msha-controller-operator-history
- **controller_controls_operator:** Myron  Olberg → M & J Construction; 1987-06-18 to 2001-03-05; source msha-controller-operator-history
- **operator_operates_mine:** NORTHERN AGGREGATE INC. → PORTABLE CRUSHER; 2001-03-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rick  Schulke → PORTABLE CRUSHER; 2001-03-06 to 2024-06-05; source msha-controller-operator-history
- **controller_controls_operator:** Rick  Schulke → NORTHERN AGGREGATE INC.; 2001-03-06 to 2024-06-05; source msha-controller-operator-history
- **controller_controls_mine:** Sharron  Olberg et al → PORTABLE CRUSHER; 2013-10-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sharron  Olberg et al → M & J Construction; 2013-10-21 to 2001-03-05; source msha-controller-operator-history
- **controller_controls_operator:** Jeffrey  Olberg et al → M & J Construction; 2013-10-21 to 2001-03-05; source msha-controller-operator-history
- **controller_controls_mine:** Schulke Family Trust et al → PORTABLE CRUSHER; 2024-06-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schulke Family Trust et al → NORTHERN AGGREGATE INC.; 2024-06-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eric  Schulke et al → NORTHERN AGGREGATE INC.; 2024-06-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kyle  Schulke et al → NORTHERN AGGREGATE INC.; 2024-06-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ronald  Davidson et al → PORTABLE CRUSHER; 2025-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald  Davidson et al → Davidson Construction; 2025-07-16 to 1987-06-17; source msha-controller-operator-history
- **controller_controls_operator:** Kevin  Davidson et al → Davidson Construction; 2025-07-16 to 1987-06-17; source msha-controller-operator-history
- **controller_controls_operator:** Kim  Davidson et al → Davidson Construction; 2025-07-16 to 1987-06-17; source msha-controller-operator-history