Making the best use of available data through better modelling and interpretation, combined with new technology to shed light on deeper orebodies are key factors in the current challenging mineral exploration market, reports Paul Moore.
According to the annual SNL Metals and Mining (renamed from SNL Metals Economics Group since recent acquisition of IntierraRMG) Corporate Exploration Strategies (CES) study, global non-ferrous exploration spending fell by 29% in 2013, dropping to $15.2 billion from $21.5 billion in 2012. The study found that exploration spending in Canada continued to decline in 2013, while increased activity was seen in Russia and the DRC. Spending in the top ten countries accounted for almost two-thirds of the worldwide exploration budget total in 2013. The top nine countries were the same as in 2012, though there were a few shifts among the ranks with Russia moving up and Peru and China dropping back. The only other change was that the DRC replaced Argentina in the number ten spot; placing the African country among the top ten exploration destinations for the first time.
Canada has been the top destination for exploration spending since overtaking Australia in 2002. In 2013, it experienced by far the largest spending decline – more than double the declines recorded by the US and Australia –lowering its share of total exploration budgets to just over 13%, its smallest share since 1999. At the same time, Australian figures decreased 25% year over year (less than the 30% worldwide decrease), leaving it only about S$25 million behind Canada.
Spending in Russia increased $20 million in 2013, making it one of the few countries to experience an exploration budget increase, but despite this nominal increase, Russia’s mining sector has seen a significant reduction in foreign investment in recent years.
Major mineral exploration drilling contractors are an important bellwether for the mood of the industry. Energold Drilling in its Q3 report in 2013 reported: “Revenue in the third quarter of 2013 compared to the third quarter of 2012 was negatively impacted due to ongoing reduced exploration spending in the junior mining segment as challenging capital market conditions continued to weigh on their ability to raise money for exploration activity. The majority of the decline in junior exploration activity has likely already occurred and while intermediate and senior players continue to focus its reserve replacement through exploration, those companies appear to remain cautious about the size of their programs and prudent in their commitments to drilling activity. As discussed in previous quarters, there appears to be no significant indication that the junior market will return to previous levels of activity for some time.”
Major Drilling echoed this in its results for the 2013 period ending October 31. “The current economic environment continues to impact drilling in the short to medium-term, particularly on gold projects where the company has seen a significant slowdown in activity in calendar 2013. Sources of funding for junior mining companies are limited, and as such many of their projects – both in the base metals and gold sectors – have been delayed or cancelled. In a number of jurisdictions, uncertainty as to the policies of host governments or issues of land tenure also continue to have an impact on results…as expected, many mining companies did not extend their drilling activities beyond their original 2013 annual budgets during the quarter” said Francis McGuire, President and CEO. However, he concluded: “Long-term, the fundamental drivers of our business remain positive, with worldwide supply for most metals expected to tighten. With the number of projects being either delayed or cancelled around the world, we believe that in the medium-term, most commodities could face an imbalance between supply and demand, and that the need to develop resources in areas that are increasingly difficult to access will increase, which should increase demand for specialised drilling. This ongoing structural change in the industry toward specialised drilling and our continued focus on specialised drilling over the years has positioned us favourably relative to the industry.”
Effective data use and management
In its regular Earth Explorer magazine, Geosoft reports that despite a steep appreciation in exploration spending over the past decade, the number of greenfield discoveries is falling every year. Narrowing this gap will require harnessing the power of big data and cloud computing, according to a presentation by Rio Tinto’s Exploration Chief Stephen McIntosh at the recent International Geophysical Conference in Melbourne. “In a lot of cases, we have the data but we haven’t got the most out of it because of time constraints and our ability to find or ‘discover’ this data,” Amanda Butt, McIntosh’s colleague and former Manager of Exploration and Geophysics, said in an interview with Earth Explorer. “Now that we can do things more quickly, and efficiently we can get more effective information out of the data.”
Developing key geophysical systems with the ability to map and integrate geology was given as a major focus for Rio Tinto. Geophysics has contributed significantly to nine of the 16 greenfield discoveries Rio Tinto has made since 1996, including most recently discoveries at the La Granja copper project in Peru. Geophysics, in particular, has become an increasingly important exploration tool as the depth of the average discovery increases. In the 30 previous years, just a few of the company’s many finds had a significant geophysical component (such as the Elliot Lake uranium camp in Canada, the Parogominas bauxite deposit in Brazil and the Rossing uranium mine in Namibia). Rio Tinto believes that geophysics will become an even more important discovery tool in the future with better collection, storage and processing of petrophysical data: “Geophysicists could do their jobs much more efficiently if they had access to quality petrophysical data,” said Butt. “But it’s not as routinely collected or as well organised as geochemical data tends to be.”
One way to cut down on the amount of time and effort required to transform petrophysical data into a reliable visualisation of the subsurface is to use 3D inversion models, and the rise of cloud computing and advancements in the technology have made the technique much quicker and far more accessible. The Geosoft VOXI inversion software service for example, leverages cloud computing powered by Microsoft Azure. At the geophysical conference, McIntosh referenced two separate techniques that accelerate the inversion process: AMIRA International’s P1022 project and Geosoft’s VOXI Earth Modelling. The former research project, led by Peter Fullagar of Fullagar Geophysics, converted EM data into magnetic ‘moments’ before inversion whereas Geosoft’s solution is to harness the computing power of the cloud for inversion.
“A lot of EM data has been collected, but historically it has been quite difficult and time consuming to invert it, try to turn it into a geological model, or constrain it in various ways so that the inversion makes sense considering what we know about the geology,” said Butt. “Ideally, you’d run a number of inversions to test various scenarios, and now we have the ability to do that quickly.”
Rio Tinto has invested in the Geosoft VOXI suite of software services and is encouraging its geophysicists – who have traditionally dismissed inversion because of its complexities – to use 3D inversion on a more routine basis in their quest for new orebodies.
Managing data has become a critical concern in the mineral exploration community, according to a global survey report released by Geosoft. When it conducted a similar survey in 2011, only 18% of respondents identified managing exploration data a matter of “critical importance.” Now 44% of them do, with another 38% regarding it as a “top 5 issue.” Data was collected from 415 organisations around the globe. The 693 respondents represented a cross-section of roles within resource and energy exploration companies, industry service providers, government and educational institutions. More than 60% were from the mineral resources industry.
Some key findings include the fact that organisations are shifting data out of the hands of individuals and onto centralised servers. Some 40% of respondents now manage their drill-hole and geological data on a centralised server with a folder or file structure, while 51% manage geophysical and other survey data this way. Respondents also want tighter control over their exploration data and a more efficient workflow. About two out of three would prefer a single commercially available platform or an in- house solution as opposed to outsourcing their data management, hiring consultants, or allowing users to manage their own data. Search tools, complicated workflows, data duplication and dependency on knowledge experts remain the biggest obstacles to data management. Most organisations spend four to eight hours on data management per week, with some spending much longer.
The two most important outcomes associated with better data management were increased visibility and transparency for reporting and attracting investors (38%) and improved discovery rates (25%). Few (7%) considered a quick return on investment to be the most important outcome.
In summary, the report found that there is a growing need for effective data management in the exploration community in order to attract investors and improve discovery rates. Although organisations are getting better at centralising their data on a single platform, “more work needs to be done to increase data accessibility, reduce duplication, smooth workflows, and lessen dependency on experts.”
In terms of product updates, Geosoft in 2013 announced the availability of software updates for Oasis montaj, Target, Target for ArcGIS and Geochemistry for ArcGIS. The updates include significant upgrades to the Oasis montaj Induced Polarisation and GM-SYS 3D extensions. GM-SYS 3D includes new options for displaying and colouring layers and the ability to create models from partial datasets. When editing models, more options are available for more intuitive identification and resolution of crossings caused by adding or editing layers. The Oasis montaj Induced Polarisation (IP) extension has a new quality control tool with dynamic linking to the IP database and pseudosection plots. While inspecting data, the pseudosection and database can be updated from within the QC tool, changes can be made to the database and those changes can be seen in the QC tool. The ability to plot IP pseudosections as colour coded symbols in a 3D view has also been added. The menu has been updated to streamline the workflow and there is now support for real world coordinates and the UBC version 5 format.
Within VOXI Earth Modelling the Upper and Lower Bound constraint builder tool has been renamed and expanded to include the creation of the starting model, parameter or gradient reference models as well as the upper/ lower bound constraints.
Barrick Gold remains the leading global gold producer from a current portfolio of 27 operating mines. The company is estimated to have amassed over 100 terabytes of geological data in addition to more than 100 years’ worth of geochemical, geophysical and remotely sensed data inherited from acquired companies. While Barrick had developed and implemented an effective Spatial Data Management (SDM) workflow, it was aimed mainly at technical professionals with an Esri ArcGIS for Desktop licence. As a mining company, there was a much larger group that required access to Barrick’s spatial data in order to make informed decisions. This prompted the organisation to look for a complementary solution that would extend access to spatial data.
“Although we have a large group of technology users and over 500 desktop licences, there are others within the organisation that do not have a licence yet require quick access to data,” said Iain Allen, Senior Manager of GIS, Barrick Gold. “We felt that we’d be able to make better decisions, faster, if this group had easy access to relevant spatial information.”
To expand access to a growing volume of catalogued data generated by the SDM workflow, Barrick implemented ArcGIS Online and created the Barrick Online Mapping Portal. Leveraging the SDM, Barrick completed metadata for over 100,000 datasets, a necessary pre-cursor to adding data to their Global Data Catalog. A custom metadata editor is used to complete the metadata; the MXDs are then published to file geodatabases stored in an MXD Repository on the network. Each night, a metadata spider harvests new metadata and adds it to the Global Data Catalogue. This allows data, now available on the Barrick network rather than individual laptops, to be searched and used long after a project has been completed. Selected datasets are then made available as Web services published to ArcGIS Online. Services can be created from virtually any existing spatial dataset – both vector and raster – including geology, geophysics, geochemistry, structure, drilling and environmental monitoring.
Through the Barrick Online Mapping Portal, Barrick data can be combined with a large collection of online basemaps. Web apps are also made available through the Portal including the Global Data Catalogue and internal Global Deposits Database, both of which were formerly standalone applications. Discipline specific data compilations allow staff to access directly the data that is most vital to their work.
“By leveraging a cloud-based platform, we’ve been able to outsource most of the administrative overhead, allowing us to make spatial data available to a much broader audience without increasing the load on an extremely busy IT department,” said Allen.
By simply opening a Web browser, senior managers can now make critical determinations such as how many sites does Barrick have around the world at various stages of exploration. Key decision makers are able to interact with the data and get a better understanding of global issues. When mine site expansions occur, relevant infrastructure data can be integrated into an interactive Web map. This may include satellite imagery, geology, protected areas, road networks and local towns. This map can be referenced to analyse changes over time and to monitor activity “outside of the fence”; as mine sites in developing countries often attract large numbers of local people, tracking the growth and distribution of this population is important in the event of an expansion.
To ensure compliance with organisational policies, ArcGIS Online allows Barrick to store data behind the firewall while hosting the user interface in the cloud. Publishing capabilities are restricted to a small group, typically the GIS expert or spatial data manager at each site or office. These specialists create and publish specific data packages around ongoing projects and restrict data access to relevant users by creating groups in ArcGIS Online. This ensures that sensitive information always remains confidential.
“The ability to keep data private is essential due to the amount of confidential information that is shared between users,” said Allen. “Security features within ArcGIS Online allow us to ensure that only users specific to a certain mine site are able to access information.”
In addition to creating site-specific data packages, Barrick is planning to leverage the MINERAL EXPLORATION cloud platform to create a travel security map for all of its mining sites across the globe. The map will display risk factors for each site including political instability, earthquakes, tsunamis, typhoons and other threats. The site-specific risk factors will be drawn from a spreadsheet managed by the Security team and any changes made will be automatically reflected on the map, providing users with a live feed of security- related updates.
Future plans include leveraging the Compare Maps template within ArcGIS Online which will allow users to view datasets relative to multiple mine sites on a split screen. Barrick also hopes to link their data catalogue directly with ArcGIS Online so that data can be searched in the cloud using metadata key words.
Artificial Neural Networks (ANN) are a comprehensive data-driven modelling approach for creation of mineral predictive maps. Based on a “self-learning” process, this artificial intelligence (AI) technology can be used to interpret almost any geo-scientific data for generation of both qualitative (prediction of locations) and quantitative (prediction of locations, grades, tonnages) mineral predictive maps. By analysing the footprints of known mineralisation in the framework of available geo- scientific data, the approach generates trained ANNs that are further used to generate predictive maps.
Experiences from over six years of research and development by Beak Consultants have been used to implement the ANN technology into the advangeo Prediction Software using the standard GIS environment of ESRI ArcGIS. The software guides the user through different steps of data preparation, network training and application, and helps to visualise the results.
At PDAC 2014, Beak Consultants, together with the Geological Survey Dept of Ghana (GSD) and the Freiberg University of Mining and Technology (TU BAF), will present the results of a research project directed towards the identification of gold exploration targets in a well-known mining district – the famous gold belts of Southwest Ghana. By using existing data from the airborne geophysical surveys, geological maps and existing mineral database of Ghana, a set of gold prospectivity maps has been created using ANN for both hard rock and placer type mineralisation. These maps can be used as key instruments for the future attraction of investment and development of the mineral and mining sector of this area. In addition, these mineral predictive maps contribute to land-use planning activities.
Entering its 17th year of operations, DGI Geoscience Inc (DGI) is a leader in quantitative in-situ physical rock properties acquisition and interpretation services. DGI says it continues to advance its 2-4C (to foresee) process: a statistically robust methodology to assess, interpret and define relationships within quantifiable geoscience datasets including physical properties as well as geochemistry, assay, geometallurgy, and geotechnical inputs. Moving forward into 2014, DGI says it is working with multiple major mining companies and mid- tiers on various projects with existing acquired geoscience data such as geochemistry and physical rock properties to characterise ore and host rocks and hence improve models and project understanding. Using a data driven approach, the 2-4C process has offered the exploration and mining industry a way to investigate, question and build relationships through multivariate data analysis.
A new service recently commercialised by DGI is a web-based televiewer browser that allows DGI clients to view the processed data on any device, such as a smartphone, tablet or laptop. Borehole visualisation through optical and acoustic televiewers has increased in use by mining and engineering firms for structural and geotechnical purposes, as well as for supplementing poor core recovery. DGI has also developed proprietary image processing routines to improve the optical results – better clarity and contrast, removing drilling artefacts – and increased partnerships with leading consulting firms in using the data more effectively and seamlessly. DGI now offers the browser as part of their services package for televiewer data acquisition and interpretation.
It has become common place within the resource industry to obtain mineralogical information at different stages of mineral exploration and metallurgical investigations using a variety of methods. These include hyperspectral analysis (thermal-, near- and short- wave infrared), quantitative X-ray diffraction (XRD), thin section petrography, and quantitative scanning electron microscope (SEM) analysis. Modern analysis of these datasets allows quantification of mineralogical parameters that can be useful for tracing hydrothermal alteration patterns and for geometallurgical studies. Similarly, suitable lithogeochemical data can be used to infer mineralogical parameters and define trace element enrichment patterns associated with hydrothermal alteration. Less common is the integration of these two data sets to provide cross validated interpretations of alteration patterns in 1, 2 and 3 dimensions. CSA Global provides integrated geochemical services that incorporate diverse data types to optimise the interpretation of geochemical and mineralogical data.
An example of this approach was provided by integrated hyperspectral and geochemical analysis of diamond drill core from the recent VG Zone discovery on the QV property of Comstock Metals in the White Gold District of the Yukon Territory of Canada. Selected major and trace elements from drill core samples reflect mineralogical changes in the felsic orthogneiss host rock during hydrothermal alteration associated with gold mineralisation. The core samples were analysed using a near-total four- acid digestion in order to obtain data that will detect changes in silicate mineralogy during hydrothermal alteration, as well as information on important pathfinder elements known to be enriched (or depleted) at the same time that gold was introduced into the rocks. A split of coarse (<2 mm) material from most core samples was also analysed using short-wave and near-infrared radiation on a HyLogger operated by Bureau Veritas Minerals in Australia. Rather than interpret the hyperspectral data simply in terms of mineralogy, spectral parameters that characterise changes in mineral composition within hydrothermally altered rocks have been plotted in order to demonstrate the correlation of the hyperspectral response with the lithogeochemical data. Trace element data extended the observed downhole width of the hydrothermal alteration halo by an additional 80% compared to gold data alone, and the hyperspectral data increased the downhole width of the halo by as much as 50%. While this case study was relatively straight forward to interpret (intercept of interest encompasses a single uniform lithology), complications introduced by lithological variations and structural complexities required an integrated interpretation of multiple data types in order to produce a rigorous interpretation.
The applicability of field portable technologies such as XRF, XRD, and hyperspectral analysis can be assessed once the characteristic geochemical and hyperspectral parameters have been identified in orientation surveys such as the one described. These data allow the recognition and definition of hydrothermal alteration patterns in the field and provides rapid targeting aids for exploration programs. CSA argues that such aids will become more important as mineral exploration shifts increasingly towards drilling buried exploration targets.
GF Instruments has introduced the 10-channel ARES II instrument for resistivity and IP tomography equipped with an extra powerful transmitter, the 850 W, 2000 Vp-p, 5A, Its advantages can be seen especially in large 2D and 3D surveys for continuous survey from water level and for programmable monitoring of structures. The unit can be supplied with power either from a 12 v battery or from a generator (via AC/DC convertor) keeping full transmitter performance both for multi-electrode cable measurement and for VES. Thus easily portable ARES II system can be used for heavy duty surveys but also under extra high or low ground resistances reaching significantly enhanced depth ranges of investigation and noise resistance for both resistivity and small changes of low IP levels. The company also states that its CMD Explorer (2.2 m, 4.2 m and 6.7 m depth) and CMD Mini Explorer (0.5 m, 1 m and 1.8 m depth) have strengthen their position in the market. Both instruments are equipped with three simultaneously working EM systems providing data for conductivity mapping and for conductivity sections using EM inversion. The data processing system supports structural models with both fluent and sharp conductivity changes convenient for 2D and 3D imaging. Built- in 1D inversion indicates parameters of two layered model (conductivities of layers and depth of border) currently in situ. Continuously seeking ways to improve the performance of its directional core drilling and borehole surveying systems, Devico has just launched a brand new core orientation tool, the DeviCore BBT. Combining Brilliant BlueMC wireless technology with other proprietary innovative features from Devico, the DeviCore BBT also integrates the DeviDip system probe technology. The tool and core barrel extension system can be quickly assembled on the drilling equipment on site. The DeviCore BBT probes are equipped with a valve system in front to prevent any slowdown of the pump-in time.
The DeviCore BBT measures inclination, orientation, gravity vector and temperature, while monitoring battery status. It uses three high- accuracy accelerometers and comes equipped with a Nomad PDA system and the DeviSoft Mobile software. Using Brilliant BlueMC technology for wireless connectivity, the results are downloaded from one probe to the PDA, while the other probe is gathering additional data down in the hole.
The company states: “Designed to provide required quality results, the DeviCore BBT is effective in a broad range of ground types and core breaks and can be used in up or down boreholes, as well as in horizontal boreholes. With two DeviCore BBT probes in each kit, the system operates without having to interrupt the drilling process to switch probes. In addition, the DeviCore BBT is covered by Devico’s unsurpassed warranty, offering 24 months of coverage on the equipment and committing to a maximum repair cost of €3000 with any type of major repairs, as long as the survey instrument is submitted for proof of damage.”
The 5-component AMT method (Audiomagnetotellurics) effectively used by AGCOS is quickly gaining ground as a highly effective electroprospecting technique for mining exploration, mainly due to its high sensitivity to orebodies of various sizes and depths. Such high sensitivity is due to the fact that the method implements two technologies at the same time: the AMT method itself (Ex, Ey, Hx, Hy) and the Magnetovariational Profiling method, MVP (Hx, Hy , Hz).
AGCOS states: “In recent years robust parameter estimation techniques for orebodies have been developed that allow the quick determination of location of exploration areas directly in the field (during the field survey). Both techniques use Earth’s natural EM field, are very portable and do not require heavy equipment and large field crews. Precision field tripods for induction magnetic sensors provide high performance and accuracy of sensor alignment, as well as the ability to carry out all-season field surveys on any terrain.” The method is effective for both the exploration of deep objects (2-3 km) and the mapping of thin dykes and veins overlaid by sediments.
Oxford Instruments has released the handheld XRF X-MET7500 Mining Analyser, which incorporates the latest detector technology, providing a combination of speed, flexibility and ease of use at the mineral exploration stage through development, mine mapping and grade control, to environmental monitoring and control.on-site mining and soil analysis. The X- MET7500 “delivers the versatility of a laboratory, right there in the field,
enabling fast and reliable analysis of the widest variety of materials, including trace elements and light elements from Magnesium.” It features a large area, silicon drift detector, optimised for mining and soil applications, providing fast analysis, even when measuring light elements, coupled with detection limits down to 1 ppm for important metals.
Jeff Jefferson, General Manager for the Industrial Analysis business said “The Mining Analyser allows potential sites to be investigated more thoroughly with minimal invasion, yet quickly and with extreme confidence, throughout the mining cycle.”
The rugged handheld analyser offers significant savings in analysis costs, as samples can be measured on-site, immediately, with little or no preparation. Operators can easily and quickly adjust the calibration with site-specific samples or create and use custom calibration settings for specific requirements. The data can be combined with GPS location information to further boost productivity for exploration, mine mapping and environmental screening.
The X-MET7000 series is equipped with a large and bright touch screen that clearly displays the analysis results as a list of compounds or in an elemental form, configured by the operator. The smart and intuitive graphical user interface is easy to learn and simple to operate, similar to that of a mobile phone. It requires no external power and can operate for up to 12 hours on a single battery charge, saving on the amount of equipment needed to be carried to often remote locations.
Geophysical surveys, especially induced polarisation (IP), apparent resistivity and magnetic techniques have become mainstream exploration tools in mining exploration in the last 20 years, in most part due to the intrinsic properties of these parameters. IP is directly associated with the presence of mineralisation, apparent resistivity and magnetic directly correlated with physical characteristics of rocks, stratigraphic units or alteration. However, geophysical techniques are much less used in brownfield exploration, generally due to a combination of factors such as extensive use of drilling as a primary exploration tool, lack of understanding of geophysics from mine operators and first and foremost poor geophysical field or interpretive results in areas of human activity. A geophysical proprietary technique, developed by Matrix.
GeoTechnologies, was used at two sites – the Lynn Lake nickel sulphide deposit and Reed Copper operation. Unique 3D interpreted geophysical and conceptual geological models were created and subsequently correlated with existing geoscientific database and results from new drill programs. Matrix states: “These case studies demonstrate how geophysics can be an efficient tool in brownfield exploration for disseminated, near-solid and solid types of mineralisation and can successfully be used to find satellite orebodies at a fraction of the costs of the conventional drilling. Furthermore, geological information is not required to interpret IP, apparent resistivity and magnetic as would be the case for the interpretation of most geophysical data or inversion programs. In our case studies, the integration of geophysics with other geoscientific data was done at a later stage and after the construction of the conceptual geological models; our interpretation and subsequent integration were completely independent of any previous geoscientific knowledge or data. In addition, the presented technique offers minimal environmental impact and offering reliable results.”
The use of modern high power systems, in the Matrix case a Walcer 9000 system, helped to overcome some logistical problems such as anthropogenic contamination, mining debris and waste or deep overburden that was previously regarded as impenetrable to achieve a significantly improved depth of exploration.
At Lynne Lake, the site operator contracted Matrix to apply its proprietary technique with the purpose of defining deeper geological structures and potentially extending known mineralisation to greater depths. At the time, the site was going through intensive rehabilitation development covering more than 75% of the surveyed grid and the presence of extensive human activity presented a significant logistical challenge. Acquired data was repeated at a 200 % rate and detailed field logs were kept to identify potential problems related to human activity contamination or effects of buried underground workings.
Another challenge was to acquire data from deeper level of exploration while maintaining high lateral resolution. A reconnaissance gradient array, specifically designed to attain 500 meters depth at 25 m reading spacing, was used to cover the entire grid in several blocks. The main objectives of the reconnaissance gradient survey were to verify the presence of mineralisation at depth and configure the plan distribution of either known mineralization or new satellite orebodies.
Based on the results of the gradient survey and in discussion with the project manager, five zones of geophysical interests were identified and selected to be detailed using a combination of several gradient arrays and pole-dipole that would provide shallower information. The detailed surveys covered the lines of interest and focused only over the most intensive and high priority reconnaissance IP anomalies. The follow- up survey results were integrated with gradient reconnaissance data and interpreted using a proprietary quantitative techniques developed by Matrix to deduce a unique conceptual geologic model of each area of geophysical interest. The interpretation of IP and apparent resistivity data showed the presence of a previously unknown mineralised causative body at depth that seemed to continue to grid south and north. The drilling program designed to test deeper targets then resulted in substantial intersection of mineralisation (47.1 m of 0.7 % nickel, 0.5 % copper and 0.02 % cobalt); re-enforcing the potential of Disco Zone as an important new resource.
Mira Geoscience supplies the mining industry with practical and cost-effective multi disciplinary 3D modelling and data management solutions for mineral exploration and geotechnical hazard assessment. Chieftain Metals Corp recently contracted Mira to model legacy IP data at their Tulsequah Chief project in British Columbia, which had located promising targets. Following the first phase of their drilling program, the 3D-IP chargeability anomaly model, in conjunction with a comprehensive re- interpretation of historic geological data, helped to determine that Tulsequah is one of the world’s highest quality VMS deposits with the strong prospect of doubling or tripling the currently estimated resources.
For this geophysical modelling effort, Mira was provided with magnetic and IP data collected in 1994. Legacy data does not always fit well with today’s continuously evolving technology, but integration of these data into a comprehensive 3D model was crucial to effective interpretation. For the Tulsequah work, Mira employed a novel inversion modelling approach to make 3D chargeability models out of IP “gradient” data, combined with a geometric compactness algorithm to generate a more geologically reasonable output.
“Back in the 1990s, many mining companies collected all kinds of geophysical data at their exploration projects. IP gradient is a good example of data that nowadays tends to sit on people’s shelves collecting dust. Many people don’t quite know what to do with it. The good news is that we can interpret these datasets with new quantitative modelling methods to yield valuable exploration results”, said Jeff Witter, Acting Director, Vancouver Office at Mira Geoscience.
Conventional 2D IP surveys typically conducted for mineral exploration explore to depths of around 100 m or so depending on the configuration. While this is sufficient for near surface targets, the depth extent beyond 100 m can not be determined without additional surveying, or drilling. Targets below 100 m may go undiscovered. The OreVision IP from Abitibi Geophysics delivers four times the depth of exploration in one survey allowing clients to better determine the true potential of deposits and prioritise drill targets all for the same cost as a conventional 2D IP survey.
In IP, the depth of investigation is determined by the distance between the transmitter and receiver dipoles, while resolution is determined by distance between the electrodes. While it is possible for a conventional IP survey to attain great depths of investigation this is achieved by using larger spacings between electrodes, thus sacrificing resolution. OreVision IP utilizes 30 receiver electrodes ensuring that the high resolution required to characterise near surface targets is maintained, while also exploring to a depth four times greater than would be possible with a conventional 2D IP system using the same electrode spacings.
Reducing water use when drilling
Products (IDP) recently assisted at a mineral exploration site in the US and utilised two of its technology platforms that are designed to provide an engineered total fluid solution. The SYSTEM 360TM unit and an BARAD-399 CORETM drilling fluid system were used in combination to achieve one of the site’s key objectives – reduced water consumption. With this combination, a simple, consistent solution was achieved that efficiently used water. Each technology platform is complemented and enhanced when applied together. The BARAD-399 CORE fluid system reduces product waste and the number of products on site; while the SYSTEM 360 unit produces proficient mixing, extends the effective life time of the fluid, and allows for water reuse.
The SYSTEM 360 unit is constructed specifically for the efficient removal of the drilled solids generated in wire line coring operations and reuse of the water phase of the removed solids. A build-up of drilled solids in the fluid can reduce its effective life, since drilled solids can deposit on the inside of drill pipe and on the bore hole wall, increase pressures, and increase the likelihood of stuck tubes. Often, when these issues arise, the fluid is simply disposed of and new drilling fluid is mixed. However, with the SYSTEM 360 unit, the rate of cutting build-up is substantially reduced along with the required volume of drilling fluid, and a high proportion of the water associated with removed cuttings can be recovered.
The BARAD-399 CORE single sack drilling fluid system is designed to simplify drilling fluid mixing and product transportation, improve efficiency of product use to minimise waste and water consumption, and reduce variation of fluid performance from shift to shift. This single product provides the functional requirements for the majority of wire line coring operations.
At the exploration site, the end result of using the SYSTEM 360 unit and the BARAD-399 CORE system was a reduction of water usage from an average of 4,500 gal/d to 2,100 gal/d. That reduction of over 53% could potentially reduce water consumption at each drill site by 876,000 gal throughout the course of a year. Ultimately, an engineered total fluid solution not only allows for a smaller footprint on a jobsite but could lead to substantial budgetary savings through reduced waste and efficient water use.
Ryan Collins, Halliburton Industrial Products Technical Manager concludes: “It is increasingly important to engineer exploration operations such that the smallest possible impact to the environment can be achieved. Part of reducing environmental impact includes water management, and one method to reduce water consumption is by improving efficiency of drilling fluid usage, since wire-line coring fluids generally are 95-99% water by volume. By focusing on the entire process from pre-use design, to application, to recycling, fluid use can be optimised.”
Foraco International, the global mineral exploration drilling services company, has developed a proprietary self-contained Solids Control Unit for removing diamond drill cuttings from drilling fluids. This innovative unit can help clients reduce their environmental impact and reduce costs for a more efficient drilling program. The self-powered
unit complete with generator and pumps, uses an especially developed decanting centrifuge to separate most of the cuttings of the main mining drilling fluids at the typical flow rate of any coring rig (140 litres/min). It enables Foraco to reduce its water consumption while coring by more than 70% and its mud additives by 60%. It can be used in as a closed loop system; cleaning the water as it isbeing used which is ideal for environments where water supply sources are scarce, working on ice and barges, and near fresh water sources where the environmental impact of possible contamination is critical.
The system is capable of removing up to 90% of fines in one pass down to 7 microns in size. There is no need for onboard shaker tables or cyclones which greatly reduces the units overall size, weight and complexity making it easy to operate or configure for field use; skid, trailer or truck mountable rigs. Another benefit of the unit is its capability to remove the solids without removing any valuable muds and polymers in turn reducing costs associated with lost product and labour. The solids control unit can be controlled by a self-monitoring Programmable Logic Controller (PLC) eliminating the need for an extra person on the drill crew to constantly monitor its progress. At this stage, in order to provide the team with a unit easy to maintain, the PLC has been removed and replaced by a more basic relays control system. Future operations will reintroduce the PLC with teams that are properly trained. The first unit has been operating successfully in the Sudbury, Ontario area for the past six months.
New survey projects
The Geological Survey of Sweden (SGU) has signed a contract with SPECIM for one of the world’s largest optical and mineralogical core scanning projects. Together with its South African partner GeoSpectral Imaging (GSI), SPECIM will scan and analyse 200 km of hyperspectral imaging data of archived drill core. The scanning will capture VNIR, SWIR and LWIR wavelength spectral images as well as High Resolution RGB image, all in a single scan. The project will result in a uniform national drill core database for further macro-analysis.
“We are looking forward to working with SPECIM. The project will extract additional information from our voluminous asset of drill cores. The information – freely available on internet – will be of great value for exploration, research and mapping” said Kaj Lax, Head of Mineral Resources department, Geological Survey of Sweden. “The drill cores cover more than 100 years of exploration. This project will transform Sweden’s mineralogical data into digitised, actionable insight.”
“The combination of SPECIM’s SisuROCK scanner and GeoSpectral Imaging’s processing solution provides the best-in-class solution needed to address the requirements of the client, the high speed and performance is what makes this project economically viable”, said Rainer Bärs, Project Manager, Hyperspectral Sensors and Software at SPECIM. “We look forward to working with the Geological Survey of Sweden as they enter a new era in their minerals information activities.”
“SPECIM has made a strategic decision to move in the supply chain from an equipment manufacturer to a service provider through internal structuring and by partnering. This contract is a confirmation of our strategy working in action,” said Risto Kalske, Chairman of the Board, SPECIM. “We appreciate Sweden taking the lead in digitising their national archive, and trust other countries will adopt similar practices enabled by new services and solutions.”
The Polish Geological Institute (PGI), has selected solutions from Guideline Geo Group within three geophysical methods; ABEM Terrameter LS for resistivity, ABEM Terraloc Pro for seismic and MALÅ ProEX for ground penetrating radar. The systems will be used primarily for mineral exploration and other investigations. “These orders are the result of our targeted activities in Eastern Europe. Guideline Geo Group is now a selected partner for PGI,” said Jonas Moberg, CEO, Guideline Geo AB. The delivery is part of a larger project funded by the National Fund for Environmental Protection and Water Management. The initial deliveries from ABEM were made in late 2013. In addition to the geophysical systems, training on the systems and the methods is included and are expected to further strengthen the contacts with the PGI.
As stated, SNL recently announced the acquisition of IntierraRMG. The new combination – SNL Metals & Mining – “reaffirms SNL’s commitment to providing the global mining industry with a one-stop source for accurate and complete data to support better decision- making.”
“Following the many enhancements SNL has made to its mining information platform in the past year, the addition of IntierraRMG marks yet another major step forward in the breadth, depth and quality of information we can deliver to clients,” remarked Jason Goulden, SNL Metals & Mining Director. “We plan to integrate our two databases and support IntierraRMG’s other business lines that are new to SNL, including strategic consulting, region- specific conferences and educational seminars.”
“Like IntierraRMG, SNL has a great reputation for quality and comprehensiveness,” noted Peter Rossdeutscher, CEO of IntierraRMG. “By combining product offerings, SNL’s clients will have the best of both companies’ individual product solutions under one service.”
In addition to the current offering available to SNL clients – data, news and analysis on worldwide exploration, development, production, planning, and acquisitions activity – SNL Metals & Mining will now provide mining claims data for more than 60 countries, complete coverage of coal and other commodities, complete coverage of early stage assets and Raw Materials Group’s strategic consulting and high-quality forecast data. Through this acquisition, SNL has also expanded its global footprint with offices now in Perth, Stockholm, Calgary, Vancouver & Toronto.
New Earth Models
As stated, with major mineral discoveries are becoming harder to find, with fewer expressed at the surface, miners are increasingly being driven deeper into the subsurface. This exposes companies and investors to much greater geological uncertainty and financial risk. Graeme Nicoll, Head of the Minerals Exploration Group at Neftex told IM: “Exploration companies increasingly need to think temporally and spatially to have a better understanding of regional geology, deposit models and drivers of mineralisation in order to explore for deeper and/or lower grade deposits. The exploration and mining industry can however benefit from the huge geoscience research budgets spent by the hydrocarbon sector who have been exploring ‘blind deposits’ and thinking along these lines for a long time. Some of their well-developed techniques for project generation and regional understanding can be directly applied to aid mineral exploration.”
Neftex is a UK-based leading supplier of global geoscience Earth Model products and services to the resource exploration industries and has developed an integrated Earth Model which spans the whole Phanerozoic and late Precambrian. Neftex states: “Our sophisticated and industry-leading global plate tectonic model can be used to understand when and where mineral deposits formed, the distribution of mineral rich areas through time and their intimate connection with differing tectonic environments. The model provides the ability to delineate and track volcanic arc activity, subducting margins, major collisional and inversion events, large igneous intrusive events and the Phanerozoic redistribution of mineral- rich Archean terranes through time. The model can therefore provide a predictive framework and global road map for future mineral exploration.”
To support mineral exploration within the Earth Model Neftex has compiled a global mineral deposits dataset with currently over 9,000 entries including porphyry copper, epithermal and orogenic gold, volcanogenic massive sulphide and IOCG deposits with an emphasis on QA-QC of deposit locations and the addition of mineralisation ages linked to citation information from the latest academic and industry geoscience sources.
He concludes: “The Neftex Earth Model rapidly provides a fundamental understanding of the spatial distribution and geodynamic context of known mineral deposits through time and can guide new exploration strategies and highlight where to go in time and space and what to expect, in terms of tonnage and grade, when you get there.”
Boart Longyear, the integrated exploration drilling services, equipment and performance tooling provider, has introduced the Drill Control Interface (DCi) to provide drilling contractors a fully electronic interface to safely and efficiently operate underground drilling equipment. The DCi allows a driller to operate a Boart Longyear LM series underground exploration drill rig and rod handler at a safe distance. The LM75 and LM90 rigs are compatible with the DCi system, and existing LM drill rigs can be retrofitted. When using a pulse width modulation (PWM) rod handler, the DCi can control both the rig and the rod handler via an integrated control panel.
“The DCi is a substantial step for increasing safety on-site by moving the driller away from moving parts and hydraulic hoses,” said Robin Maxfield, Boart Longyear Global Product Manager. “Also, lesser experienced drillers can be more productive right away because an experienced supervisor can input parameters using the DCi that guide the drilling setup.”
LM rigs can now facilitate unattended drilling with the use of the DCi. This allows the rig to complete a 3 m rod run letting drillers complete a shift change, rest or to catch up on other tasks — which increases productivity. The DCi also features one-touch rod feed and pull functionality, allowing the operator to efficiently trip rods. A wireline drum counter has been incorporated into the DCi for semi-automatic descent and retrieval of the wireline. The DCi incorporates CANBUS technology for self- monitoring and efficient operation. Complete control system integration provides immediate feedback of drilling conditions and data logging for easier reporting and analysis. Self-monitoring valves provide real-time status information, and error messages are displayed on-screen to provide assistance with any troubleshooting.
Boart Longyear provides the diamond drilling service at Olympic Dam with five diamond drill rigs drilling over 55,000 m/y. In April 2013, Boart Longyear added the new DCi control system for Rig 5, an LM75 drill rig in the fleet. It introduced automated drilling functions to operations. This consisted of five key changes to the rig, namely changing hydraulic controls to PLC controls, changing the hydraulic module of the powerpack, the installation of a number of sensors and lasers for data collection. As stated, this allows diamond drills to safely drill in the absence of an operator for a 3 m run.
Boart states that the addition of the DCi unit to Rig 5 has resulted in a monthly productivity increase of more than 13.5% with over 900 m of additional metres drilled. This has been completed during crib breaks and shift change overs. This has translated into a unit cost improvement of about $2.9/m, which worked out at 2.3%.
At Olympic Dam, the unit works well in areas of minimal variability, however, there has been difficulty in drilling more broken and variable ground conditions. A noticeable improvement was also seen in manual handling during rig moves with the reduction in weight and number of components.
Boart Longyear in 2013 was awarded a contract for the exploration drilling services at the Kibali gold mine in the Democratic Republic of Congo (DRC). The contract has an expected duration of five years and value of up to US$70 million. During the life of the contract, Boart Longyear will deploy at least seven rigs at the site and provide a variety of drilling techniques, including deep diamond coring, reverse circulation and rotary rigs for mine dewatering.
“We have had a long-standing association with Boart Longyear. We value their technical expertise and ability to drill in the most challenging conditions, and, with their help, we have discovered five other world-class gold deposits in Africa,” said Paul Harbidge, General Manager, exploration for Randgold Resources.
Energold Drilling’s manufacturing division, Dando, has added a number of new innovative features to its Multitec 9000 drill, which is a truly multipurpose drilling rig which incorporates a pullback capacity of 9,000 kg within a lightweight and compact structure. Designed for use in water well, mineral exploration, geotechnical investigation and geothermal (GSHP) drilling projects, the Multitec 9000 is capable of performing various drilling techniques including RC(Reverse Circulation), RAB (Rotary Air Blast), conventional mud, auger, diamond wireline coring , SPT, GSHP (Ground Source Heat Pump) drilling and more.
New features include remote umbilical tracking for easy tracking and control of the machine; a detachable and foldable mast section that can be fitted for the pulling of 6m drill rods; a n SPT Swing in hammer attachment (available as an option). This drop weight runs on two guides bars guaranteeing a friction free fall. The weight is fully guarded and can be quickly changed for either SPT testing or dynamic probing standards. Automatic rod handler(available as an option)for increased safety when loading drill rods.
A new safe hands-free rod handler is now available with all Dando hydraulic rotary drilling rigs including the Watertec, Mintec, Multitec and Coretec ranges. Inexpensive and simple to use, this safety feature eliminates physical lifting and manipulation of the drill rods thus increasing the safety of the drilling team when loading rods. The Dando rod handler, comprised of an arm, wrist, rotary actuator and clamping assembly, mounts to the front of the drilling rig’s breakout table and is powered by the machine’s hydraulic system. Hosed with quick connects, the unit can be easily removed for use in areas of limited space and difficult access. The rotary actuator enables the arm to swing through 135 degrees for angle drilling up to 45 degrees and the rod handler assembly has a clamping range of 2” to 8⅝” with enough power
to lift 8⅝” x 20 ft. rods. A safety shut-down system has also been fitted to the arm which prevents the operator from standing on the arm or becoming pinned between the arm and the ground.
A prototype of the world’s first Coiled Tubing Drill Rig (CT Rig) for mineral exploration was recently commissioned by the Adelaide-based Deep Exploration Technologies Cooperative Research Centre (DET CRC), established in 2010 to find more cost-effective methods of mineral exploration under deep, barren cover rock. The launch was the highlight of DET CRC’s annual conference held at the Brukunga Drilling Research and Training Facility.
DET CRC Chief Executive Officer Richard Hillis said the CT Rig has the potential to significantly reduce the time and expense associated with drilling operations to find new mineral deposits.
Instead of drill rods, the CT Rig uses a continuous reel of tubing which eliminates manual handling of drill rods (thereby greatly increasing safety) and maximises the time the drill bit is actually at the bottom of the hole drilling. The prototype rig uses steel tubing, but DET CRC is to experiment with innovative tubing materials such as carbon fibre.
The CT Rig is also much smaller and lighter than conventional drill rigs and will use a motor at the bottom of the hole as opposed to at surface, all greatly reducing the consumables (such as. fuel) costs and environmental impact.
The CT Rig will also be combined with other technologies being developed by DET CRC including downhole sensors and Lab-at-Rig technology, to further enhance the productivity of mineral exploration.
In combination with real-time sensors, the Coiled Tubing Drill Rig would radically speed up the rate of target testing. The ability to get instant feedback on the ore grade and mineral potential of the local area means zero-ing in on the deposit much faster. This is contrast to a stop-start approach to exploration requiring several campaigns of work over several years to delineate the deposit.
Strata Drilling Group recently used a Geoprobe 7822DT at a new mine site in Canada for Goldcorp Inc., the second largest gold producer in the world. The Geoprobe 7822DT is a high- capacity direct push rubber tracked multipurpose coring rig with a narrow platform for limited access areas and a sufficient stroke for added work space under the hammer. According to JohanFenelius,ManagerofGeotechnicaland Exploration Services for Strata Drilling Group in Richmond Hill, Ontario, Strata Drilling used the 7822DT on a variety of projects at the Goldcorp mining site with good success. “All of the projects came with unique challenges,” he said.
The first project was on a site where Goldcorp was constructing an open pit mine and building a berm surrounding the entire mine. Geotechnical information was collected using SPTs (standard penetration tests) in the overburden by casing the hole with hollow stem augers and using split spoon samplers until they hit bedrock. “We continued into the bedrock by rock coring 1.5 to 3 m using a BQ core barrel to confirm the consistency of bedrock,” Johan explained. “This went quite well providing our client with the information we promised to achieve.”
On a variety of other projects Strata Drilling used their 7822DT with a 3.5 in down the hole hammer (DTH) using a Symmetrix all round multipurpose concentric drilling system. The goal was to get through thick layers of scrap rock ranging in size from 6 in to the size of a full-sized truck. “Our 7822DT managed to break through the scrap rock and we cased the hole at the same time,” he continued. “Our field team retrieved a confirmatory sample of the native material at the bottom, and then completed the borehole by installing a monitoring well to monitor any leaching that may have occurred over time. We managed to do this in record time while other previous attempts failed using much different and larger machines.”
Airborne survey news
Early in 2013 SkyTEM and Xcalibur Airborne Geophysics entered into a partnership to offer a wide array of airborne geophysical technologies and services in Africa. “We are looking forward to this partnership with Xcalibur,” said SkyTem’s CEO Dr Flemming Effersø, adding: “teaming with an established partner such as Xcalibur gives us the opportunity to our reach, presence and reputation on the continent of Africa.”
Elsewhere, SkyTEM continues to serve the North American market as SkyTEM Canada Inc; in Australia the company is represented by GroundProbe Pty Ltd; and in India by SECON Aries Aerial Surveys Private Ltd (SAAS).
In May 2013, SkyTEM entered into an agreement with Minera Panama SA (MPSA) to map the Cobre Panama mine development site. The airborne data was used to map the depth of weathered rock across the site in advance of mine infrastructure planning and construction. The SkyTEM302 system was employed because of its ability to deliver accurate high resolution data from the very near surface to depths up to 100-150 m.
In new technology, following the successful launch of SkyTEM508, a powerful SkyTEM system with an NIA of approximately 500,000 NAI, the company has launched SkyTEM512. The system at 536 m2, 12 turns and an NIA of 750,000 is capable of delivering both dB/dt and B data mapping to over 500 m in depth. The very high signal to noise ratio makes it possible to collect off-time data as late as 35 ms increasing the prospect of detecting deep anomalies. The system retains the unique capability of all SkyTEM sensors to operate concurrently in dual transmitter modes – a Low Moment (LM) for early-time data and shallow imaging and a High Moment (HM) for late-time data and deep imaging. The system can be customised to maximise resolution for various geological settings. Like all SkyTEM systems SkyTEM512 has a rigid TDEM frame and a very high signal to noise ratio made possible by SkyTEM’s null coupled receiver coils.
Managing critical fuel supplies in challenging mining environments, like Canada’s North, used to involve manually checking fuel levels with a stick and a string, often under harsh conditions, especially in winter. Military forces also faced the same issue but new technology, initially developed for the military, now allows remote monitoring and fuel supply management at mineral exploration and early stage mining sites.
With this technology now available to anyone, SEI Industries, through a partnership with Varec, maker of the TacFuels monitoring system, is the first manufacturer to integrate fuel monitoring capabilities into its premium Arctic, Desert and Jungle King series of collapsible bladder tanks. The monitoring system consists of data collection units,
flow meters and fuel gauges along with a mobile laptop and rugged handheld computers which operate proprietary software and allow information from each site to be shared across secure communication networks. Using the remote monitoring system, companies can monitor their fuel volumes in real-time from a remote location; be alerted to storage issues with a leak detection alarm and to filling issues with an overfill alarm; reduce thefts and spoilage with an auditable inventory management record; and accomplish monitoring through a computer inside a building or hut.
“Remote monitoring and control technologies enable SEI tank owners to better manage their petroleum investments especially for companies with large tank farms,” says Paul Reichard, SEI’s Remote Site Division Manager. “This monitoring system takes collapsible tanks to a new level by providing remote fuel operators with a method of analysing vital statistics and the ability to plan better, operationally. By utilising the latest in hardware and software, companies can add value and safety to their remote fuel caches.” IM