Heat butter in large, heavy bottomed Dutch oven over medium heat; add onion, carrot and celery and saute until softened but not browned, about 6 minutes.
Add ground meats and 1/2 teaspoon salt; crumble meat with edge of wooden spoon to break apart into tiny pieces. Cook; continuing to crumble meat, just until it loses its raw color but has not browned, about 3 minutes.
Add whole milk and bring to a simmer; continue to simmer until the milk evaporates and only clear fat remains, 10 to 15 minutes.
Add wine and bring to simmer; continue to simmer until wine evaporates, 10 to 15 minutes longer.
Add tomatoes and their juice and bring to a simmer; reduce heat to low so that sauce continues to simmer just barely with an occasional bubble or two at the surface, until liquid has evaporated, about 3 hours (if lowest burner setting is too high to allow such a low simmer for three hours, use a flame tamer or a foil ring to elevate pan.).
Adjust seasonings with extra salt to taste and serve over linguine. (Can be refrigerated in airtight container for several days or frozen for several months. Warm over low heat before serving.).
When cooking the linguine for the bolognese sauce, don't drain the pasta too meticulously. A little water left clinging to the noodles will help distribute the very thick sauce evenly into the noodles, as will adding an extra 2 tablespoons of butter along with the sauce. Top each serving with a little grated Parmaggiano Reggiano.
If doubling recipe, increase the simmering times for the milk and the wine to 30 minutes each and the simmering time once the tomatoes are added to 4 hours.