At present, China has tungsten reserve of 55% which ranks the first in the world, among which tungsten scheelite accounts for two thirds of the total reserve. However, tungsten scheelite has less quantity in rich ore and has low grade. If explored by exist process, there will be very little economic efficiency. Tungsten concentrate has small reserve, rich ore is easy to prospect and filtrate. As a result, tungsten concentrate exploration takes up 90% of the total amount.
http://news.chinatungsten.com/en/tungsten-information/94906-ti-12209