Concor Engineering, a Murray & Roberts company, has been appointed to undertake structural engineering and civil works at the new sulphuric acid plant at Dundee Precious Metals’ (DPM) Tsumeb smelter in Namibia. Concor has extensive experience and expertise in a number of engineering disciplines to provide the erection of all structural steelwork, site fabrication of tanks, installation of mechanical, platework and piping, as well as a portion of the civils infrastructure work.
Owned and operated by DPM subsidiary, Dundee Precious Metals Tsumeb (DPMT), previously Namibia Custom Smelters (NCS), the Tsumeb plant is operated as an Ausmelt copper smelter on a toll treatment basis. The construction of the gas cleaning system and sulphuric acid plant at Tsumeb will see the processing of off-gases from the smelter and its converters, which yield high arsenic content copper. This will not only produce a downstream revenue for DPM, but will also improve the working and living conditions around the smelter, as a result of reduced emissions.
The acid plant forms part of the Namibian government’s mandate for DPMT to bring the smelter in line with international environmental standards. The plant is due for completion at the end of 2014 and based on the expected annual smelter production capacity of 240,000-310,000 t of concentrate, it will produce approximately 270,000-340,000 t/y of sulphuric acid.
Concor Engineering is subcontracting to Outotec for the first stage of the project, which includes basic engineering, site preparation, final costing and detailed scheduling. Site establishment is complete and construction has commenced. A total of 6,700 t of steelwork will be erected on site, of which 2,500 t is allocated to structural steelwork, 600 t is tank work and the remaining 3,800 t will be used in the mechanicals, piping, platework and ducting.
Concor Engineering will be given the opportunity to demonstrate its ability to quickly mobilise its resources and skilled core team to site in a remote location. The South Africa team will be supplemented by people from the local community.
Concor will train all locals using a training program developed in conjunction with the customer, to provide the necessary skills which can be retained in the plant once construction is complete. In addition to the technical aspects so important to the construction phases, the training program also covers specific safety modules that are in line with the Concor and Murray & Roberts Stop.Think.Act.24/7 safety initiative.
Due to the hazardous nature of the plant, the onsite health and safety regulations are extremely stringent. Concor Engineering has developed H & S procedures to ensure the uncompromising safety of its employees.
Tsumeb is located 430 km north of the capital, Windhoek. It is the closest town to the Etosha National Park and has a population of 14,000 people. The smelter was constructed in the early 1960s to process concentrate from the Tsumeb copper mine and is one of only five commercial-scale smelters in Africa. It is linked by rail to the Atlantic port of Walvis Bay in Namibia. The facility consists of two primary smelting furnaces, the old reverberatory furnace as well as the refurbished Ausmelt furnace.
The smelter is one of only a few in the world which is able to treat arsenic and lead bearing copper concentrates and is therefore able to conclude long term favourable contracts to treat such concentrates. Both blister copper and arsenic trioxide (As2O3) are produced from the concentrates. The blister copper is delivered to refineries for final processing and the As2O3 is sold to third party customers.
Tsumeb Smelter has become a major custom smelter with brown-fields expansion potential. It produces blister copper (98.5% Cu) and has the ability to treat complex copper concentrates.
