# Relationship history for MSHA mine 1301208

Current hierarchy: **Bill  Yohn; Laura  Yohn; Alex  Yohn → Wright Materials Company → Portable Plant #1**

- 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:** La Harv Construction Company Inc → Portable Plant #1; 1950-01-01 to 2003-07-01; source msha-controller-operator-history
- **controller_controls_mine:** Harvey E  Harms → Portable Plant #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harvey E  Harms → La Harv Construction Company Inc; 1950-01-01 to 2003-07-01; source msha-controller-operator-history
- **controller_controls_mine:** William  Yohn → Portable Plant #1; 1990-07-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Wright Materials Company → Portable Plant #1; 2003-07-02 to 2020-03-29; source msha-controller-operator-history
- **controller_controls_operator:** William  Yohn → Wright Materials Company; 2003-07-02 to 2020-03-29; source msha-controller-operator-history
- **controller_controls_mine:** Laura  Yohn et al → Portable Plant #1; 2020-02-06 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Wright Materials Company → Portable Plant #1; 2020-03-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Laura  Yohn et al → Wright Materials Company; 2020-03-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alex  Yohn et al → Wright Materials Company; 2020-03-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Yohn et al → Wright Materials Company; 2020-03-30 to current/open; source msha-controller-operator-history