Name: Colquijirca (Tajo Norte) mine.

Location: Tajo Norte is located in the Colquijirca district, of the Pasco province, in Peru.

Holding and Controlling Company: The mine forms part of the Colquijirca production unit, property of Sociedad Minera El Brocal (61.43% BVN), a subsidiary of Buenaventura.

Brief Description: The Colquijirca mine consists of three important polymetallic deposit; the Tajo Norte deposit, which contains zinc, lead and silver ores; the Marcapunta deposit, which contains an auriferous mineralization in breccia oxides, a nonarsenic copper chalcosite mineralisation, and arsenic copper enargite mineralisation as a continuation of the mineralized mantles of the Marcapunta Norte; and the San Gregorio deposit, which contains zinc.

Brief History: Buenaventura acquired shareholding in El Brocal in 1979.

El Brocal completed expansion of its Colquijirca mine's concentrator in December 2015.

Products: Zinc.

Geology/Mineralisation: The Colquijirca deposit (Tajo Norte) is structurally located within asymmetric synclines and anticlines, whose flanks are Principal-Mercedes-Chocayoc-La Llave-La Pampa; and stratigraphically located in the Calera formation (Lower Tertiary-Eocene), middle and upper members.

The base metal zone (zinc + lead/silver) is the outermost halo of mineralisation (cordillera-type) and, by volume, the zone of greatest economic importance. Its mineralogy comprises sphalerite and galena as vein ores, which occur as fracture filling and cavities, disseminations, and massive replacements.

The gangue comprises pyrite, specular hematite, magnetite, kaolin, barite, siderite, and ankerite-dolomite, as well as fluorite which is less commonly. All of them occur as fracture filling and cavities.

Native silver as filigree in cavities, and in association with siderite, has been observed near the transition zone. It is also possible to observe the occurrence of chalcopyrite-galena-dickite as filling in fractures and replacement zones.

Reserves: Total proven and probable gold reserves as at December 31, 2017, were estimated at 69.78-million tonnes grading 0.71 oz silver, 0.86% zinc, 0.36% lead and 1.01% copper.

Mining Method: Mining at Colquijirca is conducted using openpit method from which zinc and lead concentrates are produced.

Major Infrastructure and Equipment: The drills make boreholes 6.5 m deep and 6.74 m in diameter, in a 5 x 5 m grid. Once the terrain has been drilled, the explosives are placed and detonated to blast the rock.

An excavator allows for better selectivity of the ore to be transported to the concentrating plant, which is 8 km away, using 35 t payload dump trucks. A power shovel with a bucket of 10 m3 capacity is used for loading. The barren material is transported to the waste or waste-ore deposit located 1.8 km away, using trucks with a 50 t payload.

The ore from Tajo Norte is operated at Plant 2, which uses selective flotation comprising crushing, washing, sorting, milling, conditioning, flotation, and filtering processes, as well as the respective tailings storage yards to produce zinc concentrate.

Given the equipment characteristics and layout, the plant has the ability to beneficiate silver, lead and zinc ores. It has direct access to a railway, which it uses to transport the concentrates to the Port of El Callao.

Prospects: The production mix has been modified within El Brocal’s 2018 mining plan. More production will be derived from the polymetallic openpit mine than was previously announced in early 2018.

The plan is to smoothly and efficiently transition the underground operation from 8-million tonnes a day to 13-million tonnes a day.

Contact: Buenaventura investor relations Rodrigo Echecopar.

Contact Details:

Buenaventura

Tel +511 419 2500 ext 2591

Email rodrigo.echecopar@buenaventura.pe

Website http://www.buenaventura.com