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By Bob Johnson

Bob Johnson is a geologist and chairman of mining-solutions provider Maptek and the Havilah group of companies; e-mail: bob.johnson@maptek.com.au. 

As we meet the challenges of the 21st century, a range of diverse energy sources is being exploited and researched. Although traditional coal and petroleum are the mainstays of industry, change is coming.

Nuclear energy offers a good solution to greenhouse gas emission control, while alternative sources such as geothermal, which are capable of sustaining 24/7 availability, will deliver green energy for centuries. Wind and solar also will play a critical role, but will suffer from limited availability.

Industrial development models show that companies adopting innovative technology to solve operational problems move to the forefront in terms of knowledge and profitability. Axiomatically, the better the technical innovation, the better the efficiency; this operational efficiency flows through to the bottom line and positively affects long-term sustainability. Adoption of technology empowers employees to further develop the competitive advantage that innovation brings. This takes place at all levels in an operation.

For example, Maptek introduced the Vulcan 3-D mine-planning system to the world mining industry in the early 1980s, when desktop computing was in its infancy. In the coal industry, Vulcan software ensured the development of a vibrant export market for coal, produced at the lowest possible cost, because of the operational strategies that could be optimized to give miners an edge over competitors who were slow to adopt such technology.

Improving Data Currency and Enhancing Workflow

A good example is how the latest Vulcan stratigraphic modeling software significantly improves workflow. New models, created automatically from faulted (triangulation) or non-faulted (gridded) surfaces allow geologists and engineers to work with a single file that contains all the structural, quality, faulting and allied data. 

Enhanced block models ensure stratigraphic fidelity is maintained, and, on a typical mine site, one model could replace thousands of grids.

Previously problematic reverse faults and thin horizons now are easily modeled. Models can be reserved against complex 3-D solid shapes, such as pit cutbacks and mining blocks, and can contain hundreds of variables per "cell."?

At Solid Energys Stockton operation in New Zealand, for example, matching coal qualities to customer requirements is essential to maintain productivity. Substantial penalties are incurred if there are delays in mining and transporting the coal, or the blend isnt correct. Scheduling the removal of overburden and coal to match particular stockpile requirements allows the mine to confidently deliver specified products to individual customers without depleting the mines long-term potential.

Being able to accurately determine the quantity and quality of coal throughout the deposit is valuable. New drilling data are fed into the model and re-run for updated areas. The modeling has been validated by infill drilling showing that actual coal qualities conform with the models predictions. Automated scripts handle variables such as ash and swell, allowing blending to maximize value.

Block models at Stockton Mine are easily upgraded with new drilling, survey or laboratory results, and all departments are kept up-to-date with the latest information.

Output is imported into scheduling software packages, with revenue costs assigned to mining blocks, allowing engineers to generate short- to medium-term schedules that meet customer and mine requirements.

Stockton uses Mapteks Chronos scheduling package to assist with optimizing mine scheduling. Vulcans coal quality and tonnage information is imported into the Chronos spreadsheet, which includes each scheduling block broken down into all products that a pit could contain (e.g., coking coal, thermal coal, high sulphur, low sulphur, etc.). Constraint tables represent specific customer coal quality and tonnage requirements, with a range of allowable tolerances. The optimization process looks through the available reserves and picks a combination that fits the constraints.

A benefit of using Chronos for medium- to long-term scheduling is that the process can be run over several orders at once, rather than optimizing the extraction for one customer at a time. The tonnages allowable for mining from each pit can be easily adjusted during the optimization process to maximize the life of the mines higher-grade coal.

Performance Improvement

Coal mines now are heavily computerized, and all decisions are integrated into the "big picture"? of resource efficiency, environmental values and human resources. Software that allows efficient utilization and tracking of all equipment makes a quantum advance in the way mines operate on a daily basis.

At Tata Steels West Bokaro open-cut coal mines, tracking and monitoring the performance of excavators and trucks used for transporting overburden has been boosted by commissioning Mapteks Truck Dispatch system to provide real-time data. Completely configurable, Mapteks MineSuite provides accurate, reliable and relevant data that are useful for daily operations and planning as well as for making long-term strategic decisions on vehicle utilization to optimize production.

Rugged, field-mounted remote processing units (RPU) interface with graphic touchscreens installed in the operator cabin. The system is robust, with little maintenance required despite the exposure to heat, light and dust. The RPU collects valid data such as GPS position, work assignment, operator details, delays and engine run hours, and relays them to the control room.

Mining engineers can monitor the site fleet and optimize its performance. The Mapping Replay function enables users to select which timeframe and online events are to be replayed when auditing events. Reporting must be user-defined, easy to operate and require no SQL programming to be as widely used as possible across an operation.

Innovations such as online analytical processing, as successfully trialed by Tata Steel in 2008, allows fast retrieval of any data for ad hoc analysis, presented in dynamic online view, with the ability to drill down into the data. Generating multi-dimensional reports in common file formats such as Excel spreadsheets helps coal operations analyze the gap between targeted and achieved production. Management then can make the corrections necessary to improve the productivity of dumpers and excavators.

Engineering Innovation

Hardware advances in other disciplines have resulted in exciting developments such as the Maptek I-Site laser-scanning technology, providing fast survey mapping of complex and often unsafe areas.

The I-Site system allows rapid response to survey needs and provides a detailed and accurate record of progress. Nothing is left to chance, as all data are recorded in a 360-degree sweep of a scene. A concomitant benefit of the new technology is that its possible to build this equipment so minimal training is required to use it, and the benefits (technical and financial) flow quickly through an organization.

 I-Site systems are installed in coal mines in Queenslands Bowen Basin, the Hunter Valley in New South Wales and the coalfields of North America for applications such as pit survey, highwall mapping and stockpile volumes.

Coal seams, faults and other structural features can easily be identified on highwall scans, providing more accurate geotechnical information and geological models. Voids can be mapped and assessed, and data can be used to accurately measure mining progress. Simultaneous capture of high-resolution, 3-D panoramic digital images can be used by geologists to identify chemical alterations. Accurate stockpile calculations and reconciliations help operations track product assets as well as maintain accurate profiles for blending to customer specifications.

Cost savings can be realized at many stages during the mining lifecycle, such as in measuring stockpile volumes and monitoring material rehandling. Traditionally, survey methods such as GPS and total stations are used to capture stockpile toes and crests.

For a typical 300,000-ton coal stockpile, two surveyors might take three to four hours to record 300-400 GPS points, depending on the stockpile. Safety considerations may prevent access, as stockpiles feeding processing facilities often have bottom-draw conveyors.

Walking the base and using a reflectorless total station to capture peak positions leads to less-than-optimal results. With laser scanning, that stockpile takes one surveyor only one hour to scan. The total number of survey points is 1-2 million; intelligent filtering results in detailed surfaces and 3-D models generated from the best 50-60,000 points, with a tremendous improvement in volumetric accuracy.

Site-validation trials have proved that laser points match up with GPS readings; results also are more accurate. On the example 300,000-ton pile, savings of five to seen staff-days are compounded because most operations scan multiple stockpiles monthly.

Laser scanning, using the latest technology, represents the future reality of mine survey. Cutting setup by 65 percent, reducing reporting time from days to hours, increasing detail by nearly 20,000 percent, and improving accuracy are measurable performance indicators. Creating a safer, more user-friendly working environment is a strong case for acknowledging this technology as the future for survey best practice.

Reaping the Rewards

The adopters of leading-edge technologies exhibit strong operational performance, profit and become industry leaders. One strong user of technology in the uranium industry is Curnamona Energy Ltd., a soon-to-be producer of yellowcake. In the remote desert regions of South Australia, a dedicated exploration team collects digital downhole gamma logging data that are transmitted by broadband satellite link to the head office.

The exploration manager can integrate and assess the data in Vulcan, making immediate decisions on the optimum locations for the next days drilling. The tight data evaluation cycle, making Curnamona Energy one of the most efficient uranium explorers in Australia, is only possible by the commitment to aggressively use every available system to improve performance.

Complementing this, there will be a fully automated in situ uranium-recovery plant where every aspect is monitored and available online to head office staff. Tight liaison with the field teams always is maintained, with appropriate sharing of responsibilities.

In the remote desert regions of South Australia, a dedicated exploration team collects digital downhole gamma-logging data that are transmitted by broadband satellite link to a head office.

New approaches such as geothermal energy have come to the fore as geologists and engineers realize that the Earths natural heat can be tapped as a near-infinite energy source, free of carbon dioxide emissions and pollution, and, most importantly, its available every hour of the day, every day of the year.

The Earth has a vertical heat gradient of about 25ºC/kilometer. In some areas of Australia and elsewhere, the thermal gradient is almost double. If one can find and exploit these "hot rock"? areas, then the wells to extract the heat can be significantly shallower and hence less costly.

Hot rock areas are probably caused by an increase in the content of naturally radiogenic minerals, which contain higher than average uranium and thorium. As the minerals radiogenically decay, they liberate heat, which becomes trapped beneath thick sedimentary rocks "blanketing"? the deep hot granitic rock.

Geothermal Resources Ltd. is exploring for hot rocks using Vulcan to model the geology and thermal mass of the rock.

Because the geology controls the heat anomalies, its imperative that the Earths character is understood, because its expensive to drill deep exploration holes, and its even more so to drill production wells.

Although still "early days"? in the geothermal energy sector, the application of technical innovation at the engineering level will ensure its importance for our future energy supply.