# Relationship history for MSHA mine 3000950

Current hierarchy: **Graymont Ltd → GRAYMONT MATERIALS (NY) INC. → POTSDAM STONE & CONCRETE**

- 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:** Bicknell Brothers Inc → POTSDAM STONE & CONCRETE; 1950-01-01 to 1986-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Robert R  Bicknell → POTSDAM STONE & CONCRETE; 1950-01-01 to 1986-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Robert R  Bicknell → Bicknell Brothers Inc; 1950-01-01 to 1986-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Potsdam Stone & Concrete-Div/Graystone Mtrls Inc → POTSDAM STONE & CONCRETE; 1986-04-01 to 2004-07-05; source msha-controller-operator-history
- **controller_controls_mine:** Graymont Ltd → POTSDAM STONE & CONCRETE; 1986-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Graymont Ltd → Potsdam Stone & Concrete-Div/Graystone Mtrls Inc; 1986-04-01 to 2004-07-05; source msha-controller-operator-history
- **controller_controls_mine:** Graymont Ltd → POTSDAM STONE & CONCRETE; 2004-06-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** GRAYMONT MATERIALS (NY) INC. → POTSDAM STONE & CONCRETE; 2004-07-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Graymont Ltd → GRAYMONT MATERIALS (NY) INC.; 2004-07-06 to current/open; source msha-controller-operator-history