Tag Archives: SRK Consulting

Mining network needs to align on safe tailings dam design, SRK’s Spies says

Safer tailings storage facilities (TSFs) – or tailings dams – can be achieved when mine owners, contractors and engineering consultants work closely together, says SRK Consulting’s Linda Spies.

Speaking after a recent Southern African Institute of Mining and Metallurgy (SAIMM) conference focusing on tailings dams, Spies, Senior Geotechnical Engineer at SRK Consulting, said that mining executives today required more assurance that their tailings dams are safe, with controls becoming much stricter. Greater transparency was also being demanded by other stakeholders such as investors and communities, she added.

“After several hundred lives were lost in two well-publicised tailings dam failures in Brazil, in 2015 and 2019, awareness of tailings dam risks has been raised within the mining industry and in the public eye globally,” she said. “These latest failures were especially significant insofar as senior management at the mining companies were for the first time being implicated directly with charges of manslaughter and environmental damage.”

She noted that while conferences on this topic usually involved mainly tailings dam practitioners and academics, this event had strong representation from owners; contractors, who are responsible for tailings dam construction; and consultants, who design TSFs and monitor their construction.

“This meant that the discussion was more holistic and valuable, enriched with insights from these various perspectives,” she said. “This is vital in promoting innovation, safety and environmental and social responsibility in the design, operation and closure of tailings dams.”

While the tone of the event was serious considering recent failures, there was also an optimism flowing from a showcasing of best practice in the field and how this was being successfully applied. In her own case study presentation on a lined tailings dam at a South African platinum mine (Impala’s Marula dam), Spies highlighted the complexities introduced by the liner requirement – and how good drainage design and quality assurance were an important part of the solution. (see Getting lined tailings storage facilities right below)

Among the key issues discussed at the conference was whether upstream tailings dams should be allowed – as this was one of the commonalities in the recent Brazil failures. High-level input was given in a panel discussion by senior leaders from a mining company, a law firm and an insurance firm, including technical opinions from tailings industry expert and specialist geotechnical engineer Adriaan Meintjes, a Partner and Corporate Consultant from SRK.

According to SRK Principal Hydrogeologist and Numerical Modeller, Sheila Imrie, who also presented at the event, tailings is rightly receiving considerable attention from a combined engineering and scientific perspective and will continue to do so in the future.

“The continued application of the latest technologies by the industry’s top experts is critical,” Imrie said. “Industry must also ensure that sufficiently detailed research, monitoring and numerical modelling informs the future design and current management of tailings dams.”

She presented a paper on ‘3D Seepage Modelling in Tailings Storage Facility Analysis and Design for Low Permeability Lined Basins’ with SRK Civil Engineer, Wesley Rouncivell. A key aspect of the safe operation of tailings dams into the future involves comprehensive and rigorous monitoring of these facilities on a regular and real-time basis, they said.

In another SRK presentation, GIS Specialist, Ansu Louw, and Civil Engineer, Riaan van der Colf, gave their insights on a ‘GIS-enabled, Web-based TSF Monitoring Solution’ by SRK to enhance monitoring of tailings facilities.

Getting lined tailings storage facilities right

The inclusion of a liner in a tailings dam brings many environmental benefits, but also increased complexity in design, construction and operation, Spies says.

In her presentation – ‘Design of an HDPE-lined platinum tailings facility in South Africa’ – at the SAIMM Tailings Storage Conference, in Gauteng, recently, Spies highlighted the importance of well-designed drainage systems. These are vital to drawing down the phreatic surface, reducing the seepage gradient and minimising the liquefaction potential of tailings, she said.

She also emphasised high construction standards to ensure tailings dams successfully limit seepage, and outlined a series of quality control and assurance measures.

OZ Minerals Explorer Challenge winners crowned

OZ Minerals has awarded multiple prizes as part of the online crowdsourcing Explorer Challenge, organised in partnership with energy and resources open innovation platform Unearthed.

The submissions for the crowdsourcing competition to find new exploration targets at the Mount Woods tenements of the Prominent Hill copper-gold mine (pictured), in South Australia, ranged from cutting edge machine learning to advanced physical modelling, with OZ Minerals making more than six terabytes of public and private exploration data available to competitors.

The three month long competition concluded on May 31, 2019, having seen over 1,000 global participants from 62 countries register for the chance to not only win a A$1 million ($701,156) prize pool, but also have its concepts tested in real life, with the top targets scheduled to be drilled by the end of 2019.

First prize (A$500,000) went to Team Guru, a team made up of Michael Rodda (data scientist), Jesse Ober (environmental scientist) and Glen Willis (process engineering) for an approach that included interpretable machine learning models for mineral exploration using geochemistry, geophysics and surface geology.

Second prize (A$200,000) went to DeepSightX, a team made up of Dong Gong, Javen Qinfeng Shi, Zifeng Wu, Hao Zhang, Ehsan Abbasnejad, Lingqiao Liu, Anton van den Hengel, Karl Hornlund, and John Alexander Anderson. This team exploited multi-disciplinary skills at the intersection of artificial intelligence and geoscience, leveraging this to generate an artificial intelligence model to provide promising exploration targets in the Prominent Hill Region (PHR) supported by best practice geoscience.

Third prize (A$100,000) went to Hugh Sanderson, Derek Carter and Chris Green from team Cyency. Cyency has a strong data science and geoscience background, with Sanderson practising “deep learning” for several years, Carter being involved with the technical and software side of mining for over 10 years, and Green being an experienced geologist. The team said: “With so much data, it was difficult to know where to start, so we started with what we knew – the results from the Data Science Stream. We had a set of models that we knew were pretty good at predicting mineralisation across Australia, so we ran them over the tenement…we applied several data science techniques to estimate a set of candidate points, and then selected the 10 best of these.”

The Student Team prize of A$50,000 went to deCODES’ Christopher Leslie, Matthew Cracknell, Angela Escolme, Shawn Hood, and Ayesha Ahmed. A team of early career researchers from CODES, University of Tasmania, its approach was driven by considering an iron oxide copper gold (IOCG) metallogenic model, and then “striving to produce digital proxies for all aspects of that model. Our prospectivity layers were created using a mix of manual and traditional data handling methods as well as basic machine learning approaches”.

The Genius prize (A$25,000) went to Team OreFox’s Warwick Anderson, Sheree Burdinat, Kudzai Dube, Amy Leask, Alan Ryou Pearse, Ashleigh Smyth, and Nick Josephs. The brainchild of two exploration geologists, Anderson and Burdinat, OreFox has built up a team of experts with backgrounds in geophysics, data science, statistics, geology and prospecting to tackle the Explorer Challenge, using its proprietary artificial intelligence systems to analyse the data supplied by OZ Minerals as well as open source data obtained through Geoscience Australia and the SARIG database.

The Insights prize (A$25,000) was awarded to Avant Data Solutions, a multidisciplinary team consisting of data science and programming, and geological domain expertise. The team took a heavily data driven approach with verification and interpretation using geology, with the challenge tackled, first, by analysing and exploring the data in detail and finding what data might be overlooked.

The Data Hound and Fusion Prizes (both A$25,000) went to Team Phar Lap and SRK Consulting, respectively.
Team Phar Lap consists of a mathematician, a physicist, a German trained geologist and ecologist, a pilot, and a US trained geologist, offering a latticework of geosciences and data science. The consortium used a mixed approach between geological interpretation and data crunching with a strong focus on controlled learning.

SRK’s team was made up qualified structural geologists across offices in Perth, Melbourne, Toronto and Vancouver, with “the approach including the re-interpretation and/or value-add of the provided and available datasets followed by a multi-pronged and integrated targeting approach applying data-driven machine learning (based on a balanced random forest algorithm) and weights of evidence to guide a set of knowledge-driven mineral systems informed fuzzy inference solutions”, Unearthed said.

OZ Minerals Chief Executive Officer, Andrew Cole, said: “The innovators who participated in the Explorer Challenge have provided approaches to mineral exploration that we never would have imagined internally, including ways to fuse datasets together, combining multiple layers of information, and making predictions based on the extensive datasets.

“Reviewing the diverse range of solutions that have come back from this process has been truly remarkable.”
Unearthed Industry Lead – Crowdsourcing, Holly Bridgwater, previously worked for a decade as a geologist in resource exploration and definition. She believes that crowdsourcing will transform the lengthy and intensive exploration process.

“We are extremely excited by the incredible range of solutions submitted by these pioneers that can generate high quality exploration targets in an efficient way,” Bridgwater said.

“Many industry professionals and mining companies are beginning to realise that their true competitive advantage in exploration is speed, not necessarily data or technological intellectual property. I think that the ability that the crowd gives you to generate new ideas, develop solutions, and automate processes, is something that can make a big difference and provide that competitive advantage.”

Filo del Sol copper-gold-silver blueprint includes autonomous haul truck fleet

Filo Mining has released the results of a prefeasibility study, carried out by Ausenco, on its Filo del Sol copper-gold-silver project on the borders of Chile and Argentina.

The PFS envisages average annual production of approximately 67,000 t of copper, 159,000 oz of gold, and 8.65 Moz of silver at a C1 cost of $1.23/lb ($2,712/t) copper-equivalent.

It also contemplates the use of an autonomous haul truck fleet, which allows the company to take advantage of the technology’s proven productivity improvements and operating cost savings, Filo Mining said.

Filo Mining is the second development-focused company in the past few months to make plans to incorporate autonomous haulage from the off. In November, NGEx Resources said it assumed its Josemaría project in Chile would use the latest in autonomous haul truck technologies.

The Filo del Sol study contemplates open-pit mining, with conventional drilling, blasting and loading performed on 12 m benches and is based off an initial probable reserve of 259 Mt at 0.39% Cu, 0.33 g/t Au and 15 g/t Ag.

Pre-production capital was pegged at $1.27 billion (excluding costs prior to a construction decision) and the company estimated a 14-year mine life with copper cathode, gold-silver doré and a high-grade copper precipitate produced. Filo said the post-tax net present value (8% discount) was $1.28 billion at copper, gold and silver prices of $3.00/lb, $1,300/oz and $20/oz, respectively.

Filo del Sol hosts a high-sulphidation epithermal copper-gold-silver deposit associated with a large porphyry copper-gold system. The project is in the Andes Mountains on the border of Chile and Argentina, approximately 140 km southeast of the city of Copiapó.

From the open pit, ore would be trucked to a conventional two-stage crusher, designed to process 60,000 t/d of ore. Crushed ore would be treated by sequential heap leaching, to extract copper and subsequently gold and silver from the ore followed by hydrometallurgical processing to produce copper cathodes and gold-silver doré. A portion of the barren leach solution, following zinc precipitation, would be treated to avoid a build-up of recirculating copper and cyanide through the gold circuit. This treatment is based on the SART process, which produces a copper sulphide precipitate (with grades of around 65% Cu) and recovers cyanide for use in the heap leach.

Groundwater for the process plant would be supplied from nearby aquifers to the plant site, and power would come from a 127 km of power line construction to connect to the Chilean national grid.

The PFS was prepared and managed by Ausenco Engineering Canada, with input from AGP Mining Consultants, BGC Engineering, Knight Piésold, Advantage Geoservices Limited, Merlin Geosciences and SRK Consulting.

SRK and SGS Bateman to run the feasibility numbers at GoviEx’s Madaouela uranium project

SRK Consulting and SGS Bateman have been awarded for their previous work for GoviEx Uranium, with the two set to carry out a feasibility study on the company’s ’s Madaouela uranium project in Niger.

The two companies were part of the team that completed the prefeasibility study and environmental permitting work on Madaouela, with GoviEx saying both have considerable experience in uranium and African project development.

Chairman Govind Friedland said: “We are excited to commence this next stage in the development of the Madaouela project. GoviEx has steadily and actively focused on value accretion for our projects while staying in tune with the state of the market; our appointment of SRK and SGS corresponds with a recovering uranium market price. GoviEx will continue to advance our projects with discretionary spending commensurate with improving market fundamentals.”

Further recovery and cost optimisation will be the focus of the feasibility study, GoviEx said.

The key highlights from the prefeasibility study were a mineral resource of 111 Mlb U3O8 in the measured and indicated categories, and 28 Mlb U3O8 in the inferred category, probable reserves of 60.54 Mlb U3O8, forecast uranium recovery of 93.7%, annual production of 2.69 Mlb U3O8 for 21 years at a cash cost of $24.49/Ib, and start-up capital expenditure of $359 million.

Since the publication of this study, the company has added 11.67 MIb U3O8 in the measured and indicated categories (of which 5.96 Mlb relates to the open-pit amenable Miriam deposit) and 9.35 Mlb U3O8 in the inferred category, plus developed a potential process design that could improve project economics (membrane separation).

The Madoauela project is around 10 km south of the town of Arlit and Orano Mining’s mining subsidiaries of Cominak and Somair, in north-central Niger. Deposits are hosted within sandstones of the Tim Mersoi Basin. The mine permit was approved in January 2016, with environmental approval gained in July 2015.