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BATEMAN Engineering NV - Gold Processing Track Record
Feasibility study completed for Doris North at Miramar's Hope Bay
BATEMAN has been contracted by Miramar Mining Corporation to investigate the potential to install an SAG (semi-autogenous grinding) mill to reduce capital and operating costs on the proposed initial development of the high-grade Doris North gold deposit at the Hope Bay project in Nunavut, Canada.
This investigation is an extension of a feasibility study conducted by BATEMAN with other consultants, which was completed in 2003, with the objective of facilitating the rapid development of low-cost, high-return and low-risk gold production on the Hope Bay belt. Based on the results of this study, production on the Doris North deposit is targeted to commence in early 2006, subject to the granting of the required permits.
The mining of the Doris North Zone will be by underground methods, with ore hauled from underground by truck to a crusher located adjacent to the portal feeding a modular milling plant pre-constructed off site and transported to site in assembled units.
A modular concept was selected for the study as no foundations would be required for the mill, which could be set on bedrock and compacted fill and covered with a sprung structure similar to those used at a number of other arctic locations. The ore will undergo conventional crushing and grinding with an integrated, gravity, gold-recovery circuit followed by flotation and cyanidation of flotation concentrates, with gold dorŽ produced on site.
The mining resources defined within the study comprise the Doris Hinge and portions of the Central and Lakeshore veins in the limbs of the Doris Hinge vein. The feasibility study was prepared on the basis of developing the facilities for a longer-term operation than the expected two-year lifespan of the Doris North deposit, as there is significant potential to extend the mine's life through the development and mining of other resources in the Hope Bay belt. The mill was therefore designed for a maximum throughput of 800 t/day to accommodate possible future increases in throughput, even though the feasibility study considered an average throughput of 668 t/ day.
The BATEMAN modular gold-process plants for the extraction and recovery of gold are particularly suited for fast-track operations and for remote sites where construction is difficult. This is due to the fact that the plants are designed, fabricated, trial erected and water commissioned in the factory and then partially dismantled for transport to site where they can be rapidly re-assembled and commissioned.
Pre-concentrating the gold into a small volume of concentrate that can be intensively treated is another key feature of the BATEMAN modular gold plants. This feature leads to a more compact operation; minimised reagent exposure, containment and elimination; reduced leach times and circuits; and possible direct gold recovery via electrowinning, thus avoiding carbon adsorption, stripping and regeneration.
Gold-recovery complex for Uzbekistan
BATEMAN has been awarded a US$197,8M contract to revamp and modernise a gold-recovery complex for the Navoi Mining and Metallurgical Kombinat in the Republic of Uzbekistan. The complex will involve the No. 3 Hydrometallurgical plant, where a flotation process will be introduced, and the expansion of mining facilities at the Kokpatas and Daugystau gold deposits in the Kyzylkum desert. The proposed complex will process 5 Mt/yr of ore to produce 20 t/yr of gold.
The project will be funded by a structured finance package facilitated by BATEMAN. Export-credit agencies in the USA (EXIM), RSA (ECIC), Israel (IFTRIC) and Germany (HERMES) will insure 85 % of the total contract value with the remainder being funded by commercial loan facilitated by BATEMAN.
This lump-sum project has two components covering the provision of the process package for the Uchkuduk plant and the associated equipment for all three sites.
The process package primarily covers the flotation and bio-oxidation circuits. BATEMAN will supply the flotation technology to recover gold-containing sulphides into flotation concentrate which will be directed to the bio- oxidation circuit. Bacteria will be used to promote the oxidation of the sulphides in the gold ore in the bio-oxidation section of the plant, after which it will be treated conventionally. Biomin, part of the Goldfields group, will supply the process package for the bioleach section.
BATEMAN will undertake the detailed engineering design and equipment procurement and supply to site, with the client handling the construction under BATEMAN supervision. The commissioning of the plant will be done by BATEMAN in association with the technology suppliers.
After completion of the financial arrangements, the contract should become effective by October 2002 with the first deliveries to site commencing six months later and work completed in two years. Commissioning the plant is scheduled towards the end of 2006.
The project was awarded on the basis of BATEMAN’s engineering capability and ability to facilitate the required finance, together with its extensive project experience in Uzbekistan. BATEMAN is currently engaged on a US$160M lump-sum turnkey project for a booster gas-compression facility in the Shurtan gas field in the south of the country and it was the main contractor for a recovery plant installed at Muruntau for the joint venture between Zarafshan and Newmont which went on stream in 1995. This involved a very large crushing, screening and heap-leaching operation to extract gold previously considered uneconomic to recover.
BATEMAN, a global company, owned jointly by management and an international investment group, is one of the world’s leading solutions providers for creating wealth through the conversion of natural resources to marketable products.
BATEMAN’s skills include all aspects of gold-process plants and the raising of finance for projects. BATEMAN’s global presence on all five continents ensures that the sourcing of equipment for the project is optimised while the practical experience of its staff in CIS countries ensures the design and construction of the plant will best suit local conditions.
CBS expands the Taror mill
Bateman Americas, Denver, is engaged in providing the on-site construction management services for the second phase of the expansion of the milling capacity at Taror mine, Tajikistan.
This contract from Commonwealth British Services Limited (CBS) includes the basic and detailed engineering for the detoxification of the tailings received from the discharge of the CIL (carbon-in-leach) safety screen, the design of a reclaim water system for a new tailings storage area and conversion of the existing Como elution circuit to a pressure Zadra circuit.BATEMAN will also be evaluating and recommending an ozone generation plant for installation at the site and a column leach testing programme will be conducted on-site.
BATEMAN's involvement in the project commenced in late 1994 with gathering data at the CBS Taror and Jilau mines for bankable feasibility studies which were completed early in 1996.
The Taror mill was originally designed by the Soviets as a twin stream facility consisting of milling, flotation and filtration with the concentrates shipped to an off-site smelter. The facility was never completed and became non-operational when the Russians left Tajikistan.At the time BATEMAN became involved only one stream was operating, well below capacity. The first phase of the work consisted of upgrading the mill to its designed rating of 90 ton/h. The second phase, as described above, will rebuild the second stream to increase production to 200 ton/h.
Bacterial oxidation of sulphide ores
BATEMAN offers a range of services for the bacterial oxidation of refractory gold ores, copper-gold concentrates and base metal ores and concentrates.
BATEMAN is currently the engineering, procurement, construction and management (EPCM) contractor for the Kasese cobalt project, Uganda, and has conducted the engineering design based on a Mintek / BacTech process design for the LSTK (lump sum turnkey) Beaconsfield gold treatment plant in Australia. BATEMAN’s track record in bacterial oxidation technology also includes many studies on continuous stirred tank reactors and heap leach systems.
A broad ranging alliance has been formed with Mintek to commercialise the bioleaching technology developed by Mintek. Mintek has a global alliance agreement with BacTech. The technology is marketed as a package in which Mintek / BacTech provide the process design and BATEMAN the project engineering.
Bacterial oxidation is a process in which sulphide minerals are broken down and associated metals made amenable for recovery. Naturally occurring soil bacteria operating in acidic sulphate solutions at pH 1 to 2 and 35° to 50° C attack the sulphides in the minerals. After oxidation of the concentrate gold, silver and lead remain in the oxidised residue and are leached in a second treatment process. Base metals such as copper, cobalt, nickel and zinc are dissolved in the bacterial oxidation solution and can be recovered by a second process such as solvent extraction.
A bacterial process route is often indicated when arsenic is present in the mineral, as this avoids the adverse impact on the environment resulting from the pyrometallurgical processing needed to recover the metal values.
The bioleach technology marketed by BATEMAN and MINTEK has several advantages compared to other systems on the market. It offers the highest rate and extent of oxidation of sulphide. The mass reduction of the sulphide minerals by as much as 50 % during bacterial action upgrades the concentration of the metal in the residue, thus reducing the size of the plant needed for downstream processing.There is no need for pH adjustment during the process which could result in the precipitation of iron or arsenic. Such precipitation increases slurry viscosity, frothing and foaming, and in the case of gold ores, may result in re-encapsulation of the gold particles and reduced recovery. Where gold is concerned the process also offers the lowest cyanide consumption rate by the oxidised residue.
This alliance between BATEMAN and MINTEK provides optimised process design and coordinated plant commissioning. In addition, BATEMAN offers the full spectrum of project services, from the establishment of plant specifications through design, cost estimates and arranging finance, feasibility studies, procurement, construction management and commissioning.
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