Tanjianshan

Overview

The Tanjianshan Gold Mine (TJS) is located in the Qinghai Province of Western China, 80 kilometres northwest of Dachaidan. Eldorado Gold Corporation owns 90% of TJS and the remaining 10% of the JV is shared between the First Brigade for Geology and Mineral Exploration of Qinghai Province and Dachaidan Mining Limited.

Eldorado was the first North American gold producer to build and operate a gold mine in China, and with the successful completion of the Sino Gold Mining Limited transaction on December 15, 2009, Eldorado became the largest foreign gold producer in China.

The Tanjianshan property covers 338 sq km and includes four exploration licenses and two mining licenses. The mine consists of two separate deposits - Qinlongtan ("QLT") and Jinlonggou ("JLG"). The open pit mine and mill were commissioned in Q4 2006 and commercial production was declared in Q1 2007. 

 In 2011, the mine produced 115,000 ounces of gold.

Location

The Tanjianshan mine is located in the Dachaidan Region, Haixi Prefecture, Qinghai Province, northwest China. Qinghai is a relatively large province covering 720,000 sq km and supporting a population of approximately 5.3 million. Its capital, Xining, is situated in the eastern part of the province. At a local scale, the project area is located 80 kilometers northwest of Dachaidan in the Haixi Prefecture. 

The nearest large population centres to the mine site are Dunhuang, Gansu Province (265 kilometers by road to the north) and Ge'ermu (260 kilometers by road to the south).

The site is accessed by road. There is a main highway between Dunhuang and Ge'ermu or Dachaidan in Qinghai Province that passes within 12 kilometers of the plant site. The road is sealed and in good condition, ensuring year-round access throughout the area.

Geology & Mineralization

At the recently producing Qinlongtan (QLT) deposit, gold mineralization is confined to the 50^o - 60^o east-dipping fault zone which cuts across a sequence of phyllites and marbles. The shear zone is typically 5 to 10 meters wide, and is open at depth.

At JLG, surface mineralization is dominantly controlled by steeply dipping, northeast trending shear zones within carbonaceous phyllites. At depth and in the eastern part of the deposit, mineralization is associated with sub-horizontal diorite porphyry sills.

At QLT, the gold occurs mainly as fine grained free gold, is associated with pyrite and is non-refractory, whereas at Jinlonggou, gold is associated with pyrite (and to a lesser extent arsenopyrite) and is mainly refractory.

Mining & Operation

Tanjianshan is mined by conventional open pit methods using contract equipment. Mining is being carried out at the Jinlonggou (JLG) open pit at a strip ratio of 2.56:1.

In 2012 mining continues from the Jinlonggou (JLG) open pit.

Processing

The metallurgical plant is designed to handle both refractory and non-refractory ore. Non-refractory ore is subjected to whole ore CIL (Carbon In Leach), while refractory ore goes through a flotation circuit followed by roasting of the flotation concentrate. This roasted concentrate is then treated by CIL methods.

The stockpiled mill feed is fed through a single stage, closed circuit SAG mill and a classification circuit. Qinlongtan material is then fed through a conventional CIL circuit before the tailings are floated and the sulphide material removed for subsequent treatment. Cyanide contained in the Qinlongtan leach residue is destroyed using sodium metabisulphite.

Jinlonggou material is treated based on the sulphide content. If the sulphur level is low, then the material is also treated through the same CIL facility as used to pre leach Qinlongtan ore. If the sulphur level is sufficiently high the material is fed through a flotation circuit and then dewatered. The Qinlongtan and Jinlonggou flotation concentrate is then blended at a ratio of 2.1 tonne per hour Qinlongtan concentrate with 13.3 tonnes per hour Jinlonggou concentrate before being fed to the two stage roasting circuit. The two stage fluid bed roaster is fed at a design rate of 15.4 tonnes per hour.

The solid product from the roaster then passes through a mill to remove any roasting agglomerates and is then leached in a Carousel CIL circuit. The roaster off-gas passes through an electrostatic precipitator and a series of scrubbers to remove the arsenic and any remaining SO2 gas. 

The carbon is then removed from both adsorption circuits for gold removal by Zadra Methods, the gold being produced into bullion for sale.

Environment & Community

Tanjianshan is located in a very remote and isolated region of China. While it is not surrounded by local communities the company still tries to have a positive impact on them.

Each year, Eldorado sets aside US$200,000 for donation to charity projects in the Qinghai province. The company has donated money, school supplies, uniforms and computers, and has granted scholarships to students in the province. Eldorado also upgraded the Mahai Village Medical Clinic and supplied medical equipment and training for the staff.

In addition, it has donated food, water, cash, and other essential items to families in the province affected by natural disasters.