Duluth, MN, and the surrounding area have a history of stone quarrying, primarily for basalt and granite, which were used in construction and infrastructure projects. Here are some key points about stone quarries in the Duluth area:
1. Rocklin Quarry (Duluth Gabbro)
– Located near Spirit Mountain, this quarry extracted Duluth Gabbro, a hard, dark igneous rock.
– Used for road construction, railroad ballast, and building foundations.
– Operated by companies like North Shore Mining Company in the early 20th century.
2. Fond du Lac Sandstone Quarries
– Sandstone was quarried near the Fond du Lac neighborhood in the late 1800s.
– Used in local buildings and bridges.
3. Thomsonite Beach & Agate Hunting
– While not a commercial quarry, the North Shore (especially near Duluth) is known for thomsonite and Lake Superior agates.
– Collectors search beaches and old mining dumps for these semi-precious stones.
4. Granite Quarries Nearby
– While Duluth itself had limited granite production, nearby areas like:
– St. Cloud, MN (major granite producer)
– Babbitt & Ely, MN (iron ore & some stone extraction)
– supplied granite for monuments and buildings nationwide.
5. Current Status
– Most historic quarries are closed or repurposed.
– Some small-scale operations still extract aggregate (crushed rock) for construction.
– The Minnesota Department of Natural Resources (DNR) regulates modern mining activity.
Would you like details on specific historical quarries or locations where you can still find interesting rocks?