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We used desk-based and primary research interviews with key stakeholders to determine current activity within the Omani copper industry. Figure 201 shows the copper value chain with the coloured items signifying areas that are active in Oman, which include exploration for new copper deposits, wire and cable production and copper recycling.

Figure 20-1: Copper value chain active in Oman

Results from our research were presented in a workshop with industry stakeholders. Following discussions at the workshop and with the IIA the opportunity areas below were selected for further research and are presented either in the sections below or in the section on cross-industry opportunities.

Table 20-1: Opportunities selected for further research

Currently no copper mining activity is underway in Oman. State-owned Oman Mining Company (OMCO) produced approximately 19.2 million metric tons of ore and approximately 143,000 t of copper cathode during its years of operations. OMCO owns Oman’s only smelter in Wadi al Jizzi, which is not operational, currently. The smelter and refining plant started operating in 1983. In 1992, imported copper concentrates began to be supplied to supplement local production due to a decrease in ore reserves in the Sohar area¹, while for a period of time 100% of the concentrates were imported. Finally, operations ceased in 2016, partly due to changes in environmental regulations² and exhausted resources in mines.

Another company, Mawarid³, has been actively exploring for precious and base metals, and mining copper in the Sultanate since the company was incorporated in 2000. The company successfully completed mining at Shinas and Safwa in the early 2010s. During that time, they mined approximately 6 million tonnes of ore by open cut mining methods and processed it at their Lasail concentrator, which has a capacity of 1 million tons per annum⁴.

There are a number of sites across Oman estimated to have copper resources. These are shown in Figure 21‑1 and the estimated resources are shown in Table 21‑1. Based on this Oman is thought to have almost 70,800 kilo tons of ore which may contain around 1.1 million tons of copper.¹ Although none of this is being mined in Oman at the moment, there are a number of early-stage copper projects that have been identified (Table 21‑2). Mined ore from these sites would benefit from additional processing within the country in the future.

Figure 21‑1: Sites across Oman with copper resources

Table 21‑1: Estimated copper resources in Oman

Table 21‑2: List and status of mining projects in Oman

Copper pricing is governed by the London Metal Exchange prices with the amount received by the seller (e.g., mining company) dependent on the copper content of the raw material. Each step during copper ore processing results in a higher concentration of the metal in the raw material and, thus, a higher price. The value generated if Oman is to smelt and refine within the country vs export abroad is shown in Figure 21‑2, which demonstrates a clear advantage for the former.

Following mining, the ore needs to be concentrated to remove unwanted materials (gangue) and prepare it for smelting. The only concentrator in Oman has a capacity of 1 million tons per annum, which will not be sufficient to process the ore that will be mined in the country. For instance, the Washihi copper-gold project, which is the most advanced copper project in Oman, has ore reserves of 9.7 million tons at 0.88% Cu and 0.22g per ton Au. In addition, the project owners Alara announced an updated JORC mineral resource estimate of 12.4 million tons of indicated resources (0.89% Cu and 0.22g per ton Au) and 3.7 million tons of inferred resources (0.79% Cu and 0.23g per ton Au).¹ Outputs from this single project will be much larger than what can be processed by the Lasail concentrator. Furthermore, given there are other projects at advanced stages, considerable concentrator capacity will be required in Oman in the future. Thus, an investment in additional concentrator plants built at locations within easy access to these and future mining projects will help meet demand. Companies that can potentially help design and construct new concentrator plants include the ones shown in Table 21‑3.

Table 21‑3: Concentrator plant solution providers

Secondary and further processing of copper leading to cathode production will add significant value to Oman’s copper. There are two types of processes that Oman can explore: pyrometallurgy and hydrometallurgy.

Pyrometallurgy is the traditional method for copper production. This method has been used in Oman in the past by OMCO, which owns and operated Oman’s only smelter in Wadi al Jizzi. The smelter ceased operations in 2016 when copper mining stopped in Oman. Although it may be possible to restart smelting once copper mining begins in Oman, it is likely that the existing smelter is based on outdated technology that is not efficient. Updating the smelter to incorporate the latest, most efficient technology will reduce operational costs in the long run. However, this will require significant investment of approximately €700 million and significant quantities of concentrate for processing. Thus lower cost alternatives should also be explored based on mining activity in the country. These include various forms of hydrometallurgical processing.

Hydrometallurgy-based processing requires significantly lower CAPEX compared to pyrometallurgy. Given that initially, at least, the mines in Oman may not produce significant quantities of ore and concentrate to feed into a new smelter, it would be prudent to explore hydrometallurgy. Technologies include the ones described below with an overview provided in Figure 21‑3.

Figure 21‑3: Hydrometallurgy-based technologies

Atmospheric pressure vat-based leaching of copper sulphides is carried out at elevated temperatures, low pH and high chloride ion concentrations. Depending on the type of ore different leaching reactions are used (Figure 21‑4):

Ferric Sulphate Leaching

Ferric sulphate leaching of secondary sulphide ores has been successfully commercialised at the Cobre Las Cruces in Spain and Sepon copper plants, Laos. Following atmospheric leaching the leach residue is subjected to flotation to recover pyrite and elemental sulphur which is subsequently fed to an oxidising autoclave.

Chloride Leaching

Copper chloride leaching developed by Metso-Outotec is carried out in atmospheric leach reactors with cupric ions, Cu(II), in a chloride media at a pH between 2 and 2.8. The leach conditions are suitable for the leaching of all copper sulphide minerals, such as chalcopyrite, bornite, chalcocite, covellite and digenite.

Figure 21‑4. Atmospheric vat-based copper leaching.

Cobre Las Cruces is the largest private industrial investment in the province of Seville in Andalusia, Spain, of almost €1,100 Million. The project used open pit mining with the final pit forecast to be 1,600 metres long and 900 m in diameter. The hydrometallurgical plant has produced over 585,000 tonnes of copper cathode produced since production began in 2009. Turnover in 2018 was €398 M, while the complex directly employs over 800 people and indirectly over 1500 people in the region.

The hydrometallurgical plant of this complex is unique in continental Europe. The process results in the production of copper cathode (99.999% copper) using a process that is considered by the international mining industry as clean technology for obtaining copper.

Process

The copper ore is crushed in three stages to particle sizes of less than 15mm. It is then stored in a silo with capacity for 3,500 tonnes of ore. Here the wet process begins, and the mineral is further ground using a ball mill until it achieves a size of under 150 microns and is transferred to the mill thickener. Next, copper is dissolved using atmospheric ferric leaching by mixing the crushed ore with oxygen and sulphuric acid. There are eight 350 m³ reactors connected sequentially. The process takes about 8 hours and ensures copper recoveries of above 90%. After clarification and cooling, the solution is stored in a regulating tank from where it is processed using solvent extraction, a process that eliminated the dissolved impurities. The next stage is electrowinning where the electrolyte is filtered and distributed into cells through which a continuous current is passed. After about 7 days in the cells, copper sheets are harvested.

Project phases

• Start of exploration: 1992.

• Discovery (May 1994) and evaluation of the mineral deposit: 1994-99.

• Feasibility Study and Environmental Impact Assessment: January 2000 – March 2001.

• Period for approving permits required for the start-up: 2001- 2006.

• Land acquisition, Financing studies and start of detailed engineering: 2004-2005.

• Acquisition of Project by INMET Mining:

  • 70% in August 2005.

  • 100% in June 2010.

• Acquisition of Project by First Quantum Minerals

  • 100% in April 2013.

• Construction: 4th Quarter 2005 – 4th Quarter 2008.

• Start of Production: June 2009.

• Estimated production linked to the life of mine: until the end of 2020.

• Closure: 2 years for site rehabilitation.

• Post-closure Phase: 2 years.

Investment

Investment since the beginning of the project and turnover (in 2018) are shown in Table 21‑4.

Table 21‑4. Project investment and production data.

Total POX is carried out in an autoclave reactor run in a continuous manner that is designed to operate in an oxidising, acidic environment at elevated temperature and pressure. Total POX autoclaves operate in sulphate-based environments at a temperature of greater than 200^oC and pressures of between 30-40 atmospheres.

There are two principal copper concentrate pressure leaching methods commercially available: high temperature total pressure oxidation and medium temperature oxidation such as the CESL process (developed by Cominco Engineering Services Ltd, now a subsidiary of Teck). High temperature oxidation fully oxidizes all sulphides resulting in higher copper extraction (approximately 98.5% for high temperature verses approximately 96% for medium temperature) and higher sulphuric acid generation, while the medium temperature processes convert a significant percentage of the sulphide to elemental sulphur which can be disposed of in a standard tailings facility. If low grade acid is required for heap leaching activities, most mines consider high temperature pressure leaching, but if acid must be neutralized, medium temperature oxidation is preferred. Both methods are effective in the fixing of penalty elements such as arsenic.

Process

High-pressure oxygen gas is introduced into the autoclave in such a way as to maximise the dissolution of the gas into the solution phase. Once dissolved in the solution, oxygen reacts exothermically with sulphide minerals at the surface of the solid phase, forming sulphate ions that enter the solution phase (sulphuric acid). The leaching chemistry that takes place within a total POX autoclave is very complex and will vary from case to case according to the mineralogy of the concentrate fed to the autoclave. Following this, solvent extraction and electrowinning are carried out to produce copper cathode. The process diagram is shown in Figure 21‑5.

Figure 21‑5: Flow-chart for total pressure oxidation

Bioleaching is the extraction of a metal from sulphide ores or concentrates using microorganisms including bacteria and archaea. Certain bacteria and archaea can catalyse the oxidation of sulphide minerals, and hence are applicable to the copper ores found in Oman. During the process microorganisms catalyze the oxidation of iron sulphides to create ferric sulphate and sulphuric acid. Ferric sulphate, which is a powerful oxidizing agent, then oxidizes the copper sulphide minerals and the copper contained is then leached by the sulphuric acid formed.

Biooxidation

Biooxidation is an associated process involving the oxidation of sulphide minerals associated with but not necessarily part of the mineral of interest to be extracted. For example gold can be extracted using biooxidation.

A number of different types of bioleaching plants are currently operational as shown in Figure 21‑6.

Figure 21‑6: Commercial bioleaching operations

SI interviewed Metso Outotec, a Finnish company that provides solutions for Cu pyrometallurgy, hydrometallurgy (POX, Cl, Fe) and bioleaching. Based on their estimates of viability for each technology, we calculated the ore required for each category of greenfield plant. For evaluation the approximate value of known copper resources in Oman is between €6B to €7.6B.

Table 21‑5: Estimated costs of various secondary processing technologies

Ideally concentrators should be financed and owned by mining companies that have projects underway. This could be one company owning and operating a concentrator. Alternatively, a series of concentrators can be jointly funded by multiple companies to share the investment burden and be set up at locations within easy access to their mines.

OMCO should assess the feasibility of refurbishing or upgrading their existing smelter. If a new smelter needs to be constructed, the feasibility of this should be determined by the timeline of completion of the mining projects that are currently being explored, and the output from these future mines. A new smelter can potentially be funded by external investors with interest in the mining sector. The smelter can be operated on a toll basis.

Alternatively, a lower cost hydrometallurgy option can be explored if the short- and medium-term mining outputs are not likely to meet a pyrometallurgy smelter’s input requirements. Such a secondary processing plant can be funded using external investors with interest in the mining sector.

Figure Error! No text of specified style in document.-1shows the business canvas for processing. Future mining operations in Oman mean that there is the opportunity to process copper ore and sell higher value copper cathode both within the country and export abroad.

Figure ‑1: Business canvas for processing

• Identify ideal locations for a network of concentrators that mines can feed into.

• Invite engineering companies to assess ore that will be mined and design process flow for concentrators.

• Determine whether OMCO’s existing smelter can be refurbished or if a new smelter is required.

• Explore hydrometallurgy as a lower cost option if future mining output will not meet input requirements of a new smelter.

All  opportunities are listed below in their respective clusters. Click on each opportunity to find out more.