Although the valley where Rayside-Balfour is located is known primarily as an agricultural region, it also has a mining history. As early as the late nineteenth century, prospectors and geologists showed interest in the region. In 1897, James Stobie discovered mineral deposits on the banks of the Whitson River in the Township of Balfour. He sold his land to Orford Copper Mines Ltd., which opened a mine that same year.
Also in 1897, Alphonse Ollier (a French prospector) discovered ore on neighbouring lands. From 1903 to 1924, Ollier tried to obtain financing to establish a mine but did not succeed in capitalizing on his discovery. He soon sold his lands to Treadwell-Yukon Mining Ltd., (a company that Joseph Errington convinced to settle in the region) and it wasn't long before several farmers were also handing over their land. The company built three mine shafts including the Errington main mine.
Although the ore found in these deposits was very rich, the structure was such that mining it was complex. Treadwell-Yukon Mining Ltd. built an ore processing plant to determine the most appropriate processing method. This pilot project continued until 1930. The company hoped to build a plant that could process 2,000 tons of ore but the Great Depression which swept the continent put an end to this dream. Mining operations ceased in 1932 and did not resume again until 1952 and only lasted five years.
Over the years, several companies and prospectors took an interest in the region. Among them were Joseph Errington and Thayler Lindsley, whose name appears in the directorship of Sudbury Basin Mines, Sudbury Nickel and Copper Company, and Ontario Pyrites Company. This last company merged with Giant Yellowknife Mines Ltd. in 1960, and was itself purchased by the Royal Oak group in the 1980s. Around 1990, Falconbridge held a majority interest in the property previously held by Consolidated Sudbury Basin.
Other mines existed in the region including Stobie Falls Mine, Balfour Mine, Creighton Gold Mine, and Gordon Coal Mine. The quality of the ore found was poor and these mines were only in operation for a few years. Nevertheless, they contributed to the economic development of Rayside-Balfour by creating well paid jobs and encouraging the purchase of supplies from local merchants.