 Complete the following phrase:  Gold is often found in Siberia; currently the principal mining districts are in the Patom Highlands Olekma-Vitim region of the Lena Valley. During the period 1910-1914, the Siberian gold mines extracted an average of 46,655 kg and employed 57,000 workers. Exploited deposits are of placer gold. The joint British Russian Company, Lena Gold Mining Joint Stock Company Lenzoloto, owned and operated the Lena Goldfields -- much of the regions gold production. Their mistreatment of workers ultimately led to the 