Pueblo Viejo

The project is located 15 km west from provincial capital of Cotui and approximately 95 km northwest of the national capital of Santo Domingo in the central part of the Dominican Republic on the Caribbean island of Hispanola in the province of Sanchez Ramirez.

The balance of interest is held by Goldcorp Inc.

Pueblo Viejo is expected to have average annual life-of-mine production of between 575,000-600,000 ounces of gold over its 20 year mine life. Proven and probable gold reserves total 18.1 million ounces gold, 2.6 billion pounds zinc, 358 million pounds copper, and 88 million ounces silver.

Gold ore will be mined by conventional open pit methods from two pits: Moore and Monte Negro. The mines will follow a conventional drill-blast-load-haul mining sequence. The ore from the mines will be hauled to a crusher near the plant site or to the low-grade stockpile.

Over the life of actual mining, 44% or the ore will be processed and 56% stockpiled. The mine operates at an elevated cutoff for the entire life of the active mining. After the mine is exhausted, the low-grade stockpiles are reclaimed and processed. The mine will be exhausted in a little less than ten years. The low-grade will be processed for an additional ten years.

The crushing and grinding circuit uses high-pressure grinding rolls (HPGR) and ball mills. The ore is delivered by 135 t haul trucks from the open pit. The primary crushing circuit is designed to crush 18,000 t per calendar day and consists of a hydraulic rock breaker and vibrating screens. As the ore is weakly acidic, about 5 kg/t limestone will be added to the crusher feed to minimize equipment corrosion. Limestone will be mined in three separate quarries. A secondary MP800 cone crusher will be installed to crush the plus 50 mm material to 100% passing 50 mm.

The grinding circuit consists of two HPGRs in parallel which feed two ball mills (7,000 kW each, c/w VFD) in series, two cyclopaks (6 of 838 mm diameter for the first ball mill, and 8 of 660 mm diameter for the second ball mill), two vibrating screens for the first ball discharge, and two vibrating trash screens.

To treat 1,200 tonnes of sulphur per calendar day three autoclave trains will be installed. The autoclaves operate at 230°C and a gauge pressure of 500 psi (3,450 kPa).

The oxidized slurry is maintained at an elevated temperature and ambient pressure for several hours tin four stainless steel tanks to dissolve the basic ferric sulphate that has formed in the autoclave. Hot cured slurry is pumped into a cooling tower. The CCD washing circuit consists of three high capacity stainless steel thickeners 65 m in diameter. The CIL circuit consists of six carbon steel tanks with a total of 18 h to 24 h retention time. Each tank is equipped with an agitator and two KEMIX interstage screens sizing at 28 mesh (600 ìm).

The loaded carbon from No.1 CIL tank is separated and washed on two vibrating screens, and after washing, is transferred to the acid wash vessels in the refinery circuit. The loaded carbon is acid washed in four vessels. Each coned vessel is capable of treating 12 tonnes of carbon in a batch. The pregnant electrolyte is pumped from the pregnant holding tank to four parallel electrowinning (EW) trains, each having three EW cells connected in series. The filtered gold sludge is loaded into boats, and then dried and heated to 1,000°C in an electrically dried mercury retort furnace. The dried cathode sludge is then mixed with fluxes and smelted in three 500 kg capacity electric furnaces rated at 200 kW. The furnace melt is poured to make gold doré.

The pit waste rock is acid producing and is not suitable for road base material, road construction, or topping material. All such construction and road maintenance materials will be derived from the three limestone quarries.