ALPPROJECT Cons. carries out a complex of field geological studies including field evaluations, exploration, mining, petrographic, mineralogical operations and other geological works. The consortium is experienced in implemeting the above operations, including contracts with such foreign companies as Cameco, Mitsui, Apex, Newmont, Barrick etc. The companies incorporated in the consortium employ staff of the highly skilled employees and all necessary devices and equipment, including computers furnished to work in field conditions, FM-radio communication units and other equipment.

    In 2006-2007 ALPPROJECT Cons. in collaboration with emloyees of Micromine Pty Ltd. develops the unique method of 3D-modeling for estimation of prospected reserves on early stages of geological explorating works:

Optimisation of early-stage exploration of mineral deposits and method of estimation of prospected reserves in mountainous regions

Exploration in mountainous regions has a number of specific features that make the standard methods used in flat areas inappropriate, ineffective and very expensive. Exploration drilling on a dense regular grid that is used everywhere in a flat country, for example, cannot be practically used in the mountains because it would require the construction of a road to every drill pad that required blasting. This would involve a significant investment of funds and take a considerable amount of time. Alternatively, hard rock exposure in the mountains is good in most cases, and qualitative examination of the area from the surface, that includes mapping and sampling, makes it possible to define an in-depth structural model of the ore zones for minimal cost and within a short period of time. Therefore, we suggest that the method described below is the most appropriate and cost effective method for early-stage exploration in mountainous regions. 

Stage 1: The collection of historical data

At this stage, a detailed knowledge and understanding of the target area and its flanks must be developed. Historical reports, topographic maps, aerial photos and space images must all be collated. Verbal and written consultations must be undertaken with any specialists who were working in the target area and adjoining areas in the past. All pertinent and potentially useful information must be identified and extracted from the collected material.

 Stage 2:  The processing of documentation and the georeferencing of maps and images

At this stage all historical material is analysed and sorted. Further processing is as follows: 

-                    Documents are scanned and compiled as electronic books with a user-friendly system of internal and external hyperlinks. Specifically each book should have hyperlinks from the table of contents to each chapter of the book, and there should also be hyperlinks from the table of contents to scanned maps, schemas, sampling plans and other related material

-                    Images and maps should be scanned at both a high and a low resolution; high resolution for further processing and analysis, low resolution for hyperlinks in associated documentation

 

As a result, a well-organised and easily accessible electronic library of historical material is compiled, which eliminates any further use of (often fragile or poor quality) paper documentation. Further processing of high resolution images and maps involves the selection of any images or maps that can potentially be georeferenced using the coordinate system that will be used for all future project work. This selection process will usually include all geological maps, sampling plans and field work maps. It is essential that all existing topography maps (largest scale available), aerial photos and space images are also included. Each selected map is loaded and georeferenced using MICROMINE or a desktop GIS software application. Before georeferencing, all raster images must be ortho-rectified to remove any deformations and distortions. After this has been done, the maps should be georeferenced using the UTM WGS 1984 coordinate system, which is widely-used and considered to be GPS compatible.

 Stage 3: Digitising of historical maps

At this stage, all relevant spatial information is digitised from the rectified and georeferenced maps. Spot heights, elevation contours, falls, rivers, creeks, roads and trails are digitised from topographic maps. An important task at this stage will be to assign elevation values to contours and spot heights. Once this has been done, aerial photographs can be georeferenced using the topographical data obtained. This will provide a spatially accurate photo plan. Ore bodies, ore zones and spots, anomaly zones and spots, ore occurrences, samples and all workings should be digitised from geological maps.

 Stage 4: Field work. Phase 1

 Once all the spatial data has been computerised and arranged as a multi-layered thematic map, the first phase of field work can be planned. During this initial phase, the areas in which different types of field work will occur must be identified. In most cases, field work will involve the detailed structural mapping of prospective areas, together with a detailed study of the zones of jointing at the points of reference, sampling along geological traverses, formation sampling for petrographical and mineralogical analysis, geochemical soil sampling on a regular grid, the photography of outcrops, alteration zones, and bed rock and formation samples. The resampling of previous workings is also applicable. During field work it will also be necessary to record the GPS position of all previous workings found in geological traverses and other indicative points of the landscape (height points, junctions of the rivers etc). This must be done in order to correct the georeferencing that was applied to previous maps and particularly sampling plans. The point to note is that even published topography maps can have a bias up to one millimetre in map scale. After analysing the GPS positions, an average map offset can be calculated and used to correct the georeferencing of raster and vector maps.

A report of the field work should be presented on CD or DVD and should contain the following: 

-                    Register of samples

-                    Brief text report in HTML format with photos

-                    Scanned primary field documentation

-                    Geological map and map of the field works as multi-layer GIS map with legends and hyperlinks to primary field documentation, photos and geological sections

-                    Legend to geological map that shows the history of geological aspects of the studied area, including compositional petrology and all accompanying processes such as ore parent. The legend is available in a spreadsheet or image.

 Stage 5: Field work. Phase 2

The second phase of field work must be carefully planned. Assay results are posted to corresponding layers of the reporting map, thematic layers with grades and geochemical anomalies are created. At this stage a 3D model of the area is generated using MICROMINE software. This model should include all the data described previously, all historical sampling data, drillhole data etc. To be able to build a model, attributes such as strike, dip, age, depth and priority of all contacts, faults and thrusts must be specified. Even based on a relatively small amount of sampling data, a qualitative 3D model of the area can be built at this stage. During the modelling process the structure will be identified and prospective ore zones will be modelled to the correct depth. The derived model can be used for the estimation of prospective unclassified resources. However the main goal of this modelling activity is be able to visualise the whole area and its anomalous zones in 3D, and be able to quickly generate cross-sections in any direction. This allows for the identification of the most prospective zones so that further field work can be scheduled in those zones. This work will involve setting accurate locations and directions for drilling so that a minimal amount of drillholes need to be drilled in order to confirm and correct the model. The second phase of field work can thus be planned in the most accurate, optimal and cost effective way. The results of this work (even negative) will serve to correct the model further, and provide a truer picture of the area under investigation.

Once it is reasonable to start field work within identified prospective zones, the field work will include the following: 

-                    Geochemical sampling on the dense grid

-                    Qualitative collection of standard samples from trenching and bulldozer stripping. This type of sampling can be set equal to the drilling of the horizontal holes, although it is much quicker and cheaper than drilling

-                    Construction of the roads to one or several drill pads and drilling holes with strictly specified azimuth and dip

-                    A high detailed topographic survey by means of high precision GPS, DGPS and Total Stations. These tools are also used for high precision survey of the drillhole collars, trenches and bulldozer stripping

Stage 6: Field work. Phase 3

Phase 3 will also need to be carefully planned. Assay results from the previous stage will be posted to the corresponding layers of the reporting map and the 3D model. Thematic layers with grades and geochemical anomalies will be updated. The 3D model will be updated with assay results and the prospective areas will be corrected. The 3D model will improve more and more as each new package of data is applied. If the assay data is sufficient, then it will be possible to label prospective zones in the model as ore zones, ore blocks or even ore bodies. Resource estimation and classification can then be conducted. 

If the assay data or other data is insufficient, then further field work for phase 3 should be planned which includes the following:

-                    Qualitative collection of standard samples from trenching and bulldozer stripping

-                    Construction of the roads to one or several drill pads and drilling holes with strictly specified azimuth and dip

 

At the completion of this work and after getting back the assay results from the lab, the reporting map and the model can be updated. The amount of data in the model now should allow a full resource estimation and classification of the area to be conducted. At this stage our goal is achieved. Further stages of field work are not considered relevant to the early-stages of exploration of mineral deposits. However, the 3D model created during these early stages will be an essential input during later stages, including pit design and mining. This is an important benefit of the proposed method.