Located in the central province of Henan in China, the Ying Mining District has been intermittently mined over the last several hundred years by small-scale local miners. Since 1956, extensive geological mapping, airborne magnetic surveys, stream sediment geochemical surveys, local IP surveys and trenching were conducted in the area by provincial geological bureau teams, culminating in the establishment of resource estimates in late 2003.
In March 2004, Silvercorp acquired its flagship Ying silver-lead-zinc project, and has subsequently acquired three other adjacent projects (the HPG, TLP and LM mines) in 2007, consolidating its hold on the district. Silvercorp's Ying Mining District now includes 4 exploration permits totaling 44.29 km2 and 5 mining permits covering 26.73 km2. The district is located near the county of Luoning approximately 240 km southwest of Zhenzhou, the capital city of Henan Province.
Silvercorp's four mines in the Ying Mining District are held in two Sino-Foreign Cooperative Joint Venture companies. The flagship Ying Mine and the TLP Mine are held by Henan Found Mining Ltd., owned 77.5% by Silvercorp and 22.5% by the Henan Non-Ferrous Geological & Mineral Resources Co. Ltd. (the local quasi-government owned geological bureau).
The HPG Mine and the LM Mine are held by Henan Huawei Mining Co. Ltd., a Sino-Foreign Cooperative JV company owned 80% by Silvercorp and 20% Luoning Huatai Mining Development Co. Ltd. (a private company).
Mineral Processing - Silvercorp's Mills
Silvercorp owns and operates two floatation mills in the Ying Mining District. The first mill, with a capacity of 1,000 tonnes per day (tpd), was built in 2006 at a capital cost of $6 million. The second mill was completed in December 2008 with an initial capacity of 1,500 tpd and cost $12 million to build. During the second quarter of fiscal year 2012, Silvercorp expanded the second mill capacity to 2,200 tpd bringing the Ying Mining District’s total milling capacity to 3,200 tpd.
The processes used in the mills are typical of polymetallic Pb-Zn ores. There are two stages of ore crushing, from 400 mm to 15 mm, followed by ball milling such that 70% of the material passes 200 mesh (74 microns). The minerals are then separated by a series of flotation circuits, producing a lead concentrate (carrying the silver) which averages 69% lead, and a zinc concentrate which averages 52% zinc. A quality control laboratory processes up to 100 samples per day using wet chemical analytical and Atomic Absorption Spectrophotometry methods.
The concentrates are of premium quality, containing very little arsenic (less than 0.001%) or other penalty elements. Metal recoveries to date have averaged over 95% for lead, 90% for silver and 72% for zinc. The silver and lead recoveries exceed those expected from the design specifications. The concentrates are currently being transported via trucks to custom smelters located 70 to 190 km from the mill site.
Please see our latest NI 43-101 Technical Reports for Ying (SGX), HPG & TLP-LM by clicking here or at SEDAR (www.sedar.com).
Last updated Oct 11, 2013