At least three personal computer- based software systems are being marketed in Canada. What follows is a brief description of the strengths and weaknesses of each according to the manufacturers and a selection of users. For further information on any of the systems described, circle the appropriate reader reply card number on the yellow card inserted in this issue. The numbers appear at the end of each description. GEMCOM GEMCOM Services of Vancouver, B.C., is marketing five pc-based software packages which deal with exploration data, geological modellin g of orebodies, open pit mine design, open pit survey data, and most recently, grade control data in open pit mines. The system originally was developed in South Africa. The individual packages are called PC-XPLOR, GEO-MODEL, PC-MINE, MINE-SURVEY, and ORE-CONTROL, respectively. The company has more than 250 systems in operation around the world, says Stephen Cheeseman, GEMCOM’s geologist and marketing representative.
PC-MINE evaluates orebodies and plans open pit mines. It can receive data on up to 1,000 drill holes and up to 100 different rock types. Once in the computer, these data are modelled in 3-dimensional blocks by the geostatistical methods of inverse distance or block kriging. The model can be edited on the screen and reserves calculated based on a certain cutoff grade. Various open pit designs then can be generated and evaluated independently. For added flexibility, these can be generated from top-to- bottom or from bottom-to-top. This means the computer can be used to model ore stock piles as upside-down open pits, for example. Mineable reserves are calculated either by cutoff grade or rock type.
Two-dimensional models also can be generated using either inverse distance or kriging methods. In addition, the system has a mine-scheduling and short-term planning module.
GEMCOM’s survey package features the ability to incorporate non- topographical features, interpolate cross-section profiles, calculate mined volumes and quickly create plots at various scales and levels of detail.
In the case of ORE-CONTROL, the most recent addition to the GEMCOM collection of pc-based systems, the location of each blasthole in a given blasting pattern is defined by mine co-ordinants. This information, along with an assay value determined from sampling the drill cuttings, and the name of the rock type in which the hole was drilled, is entered into the computer. (For base metals producers, the system has the capability of storing multi-element assays.) This information then is displayed on the screen. Different colors distinguish the various rock types and lithologic boundaries are graphically recorded on the computer by the mine geologist. The perimeter of the blast is also recorded graphically. The polygon described by the blast then is given a name for identification.
ORE-CONTROL then estimates the grade of the block of ore to be blasted by kriging the assay values into 10×10-ft grid cells. Polygon or inverse distance interpolation methods can be used also, at the discretion of the user. At the Similco open pit copper mine, in Princeton, B.C., the system typically can predict within 3% the grade and tonnage of ore in a given mining block, says Thomas Kerr, Similco’s chief mining engineer.
The color-coded kriged grade values are displayed on the screen over blasthole location symbols and lithologic boundaries. From this display, the grade control engineer can record, graphically, zones of high- and low- grade ore. These zones are outlined and the information plotted on paper. This then is used as a digging plan for shovel operators and pit foremen.
To cut down on the movement of the muck pile during blasting, Similco uses a technique called choke blasting. According to this technique, some of the muck from a previous blast is left piled up against the free face of the next blast. This way, the muck is not cast out on to the pit floor. This technique renders the digging plan more accurate. In fact, the grade control engineer uses the plan to stake and flag the ore zones.
All GEMCOM systems operate on IBM PC, XT or AT microcomputers, or on compatible machines equipped with 640 kilobytes of memory space. Circle Reply Card # b b LYNX Geosystems
LYNX Geosystems of Vancouver has developed two software packages which offer several advantages in the modeling of complex geological formations. The larger LYNX system runs on a multi-user, networking, UNIX environment whereas the smaller, less powerful, MicroLYNX runs on IBM-PC or compatible computers. Both systems use an extension of integral calculus as its prime operating principle. This principle, which allows the operator to draw any type of shape and calculate volumes with precision, is used throughout all the data-management facilities offered by the company. System facilities include surveying, orebody-modelling, underground and open pit design and mine management.
“Having this common operating system for all our facilities gives our clients the necessary detail they require to model anything in many different mining environments” says Ed Rychkun, president of LYNX. For the large mining companies, this translates into reduced costs for hardware and training. The microLYNX system can be used by individual field offices to collect and manipulate data whereas the larger LYNX system can be used for more detailed modelling.
LYNX, which has been marketing its systems for about two years, has roughly 200 sites throughout the world, Rychkun says. Canadian clients include: Inco Ltd., Pamorex, LAC Minerals, Cominco Ltd., Giant Yellowknife Mines and Luscar Ltd.
The LYNX system completely relies on available data for its control points. A set of interconnected triangles is formed by three data points, each of which has a particular grade and elevation and is used to model complex geological surfaces. The size and orientation of the triangles are defined by the three control points at the vertices. The triangles then are transformed into plates by projecting them in the third dimension. This way, the computer can be used to model discontinuous thin-seam orebodies with considerable accuracy. The grid-cell method used by other systems requires data to be continuous. Since all data at the control points (the vertices of the triangles) are 100% accurate, this modeling technique eliminates the smearing effect of grid cell modeling techniques, says LYNX Chairman Simon Houlding.
Once the geometric model has been created, classical interpolation methods or kriging can be used to determine the value of the orebody. The completed orebody then can be plotted in plan view from any elevation, in section view along any section line, or in isometric view from any desired angle.
The LYNX system has been carried through into the mine management area to allow mine operators to compare what has been actually mined with what was planned. Depending on the level of sophistication required,
this can be done on either the LYNX or the microLYNX systems.
For the microLYNX system, the company typically conducts a 4-day training session in Vancouver or at the mine site for new clients. The operators then go off to the mine to use the system and subsequently return for more training if necessary. The cost of training is charged over and above the cost of the system. Training on the larger LYNX system is more involved. It requires about two weeks of initial training followed by two months of practical use, then a 1-week refresher course. Circle Reply Card # b b Surpac
About six years ago, Australian mining engineers at Surpac Mining Systems Pty. in Perth began applying a so-called “open” data presentation method called “strings” to geological and survey data stored in a personal computer. They found that this graphical technique allowed them to design open pit mines with ease and flexibility by drawing many alternative designs which then could be compared economically. The string technique was borrowed from the related field of highway design in civil engineering. Today, it is available to mine engineers worldwide for both open pit and underground mine design. Moreover, it has evolved to the point where it has become the design tool of choice for about half the mines in Australia (including 66% of all Australian gold mines).
Yet the company is not solely an Australian supplier. Surpac now has nine offices worldwide serving 150 client companies with 250 individual installations. “We think we’re the biggest in the world,” says Chris Cusack, mining surveyor for Surpac. He recently was in Toronto to set up Canada’s first Surpac sales, distribution and support office. That office will be run in conjunction with Mine Development Associates (MDA), a relatively young mine engineering consulting firm based in Reno, Nev. MDA has a marketing agreement to supply the Surpac system to mining companies in the U.S.
The system has four methods of modelling geology, survey and geometric mine design information. All are based on the open structure of strings for maximum flexibility in bringing data into the system (from independent survey field data- collectors, for example) and operating with other software packages (such as Lotus 1,2,3 and AutoCAD). (An open structure refers the storing of data in ASCII files or ASCII-transportable files.) The four ways data are modeled by Surpac are:
* the 3-dimensional method, which uses point data for a truly 3-D representation;
* the 2 1/2-dimensional method, which uses a series of 2-D representations to represent a 3-D body through interpolation;
* the grid modeling method, which enables shunting from string files to block files; and
* the digital terrain modeling method, which uses a contiguous series of overlapping triangles; the triangles connect data points so as to contour the information.
Surpac, whose representatives spent a morning at The Northern Miner Magazine demonstrating their system, listened to its clients, and this approach has resulted in a number of practical improvements in the system. The company also insists on keeping the structure of the system open for maximum flexibility. That means individual operations can tailor the system to meet their application. Circle Reply Card # b b
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