Welcome to Mid River Minerals Mid River Minerals, established in 1995, is a full service, custom blending and packaging facility located in the heart of America. From providing packaging service of 50 lb. to 4000 lb. of single bulk products to custom blending 9 different ingredients into a single package, Mid River will not be out performed. Using the most modern equipment, tolerances are maintained to within 1% and quality never suffers through the use of SPC?s.