479:
160:
33:
716:'s) Busang were alleged to be 200 million ounces (6,200 t), or up to 8% of the entire world's gold reserves at that time. However, it was a massive fraud and there was no gold. The core samples had been faked by salting them with outside gold. An independent lab later claimed that the faking had been poorly done, including the use of shavings from gold jewelry. In 1997, Bre-X collapsed and its shares became worthless in one of the biggest stock scandals in Canadian history."
81:. There are different estimation methods used for different scenarios dependent upon the ore boundaries, geological deposit geometry, grade variability and the amount of time and money available. A typical resource estimation involves the construction of a geological and resource model with data from various sources. Depending on the nature of the information and whether the data is hard copy or computerized, the principal steps of computer resource estimation are:
556:
each block differ. The grade, density, rock type and confidence are all unique to each block within the entire block model. An example of a block model is shown on the right. Once the block model has been developed and analyzed, it is used to determine the ore resources and reserves (with project economics considerations) of the mineralized orebody. Mineral resources and reserves can be further classified depending on their geological confidence.
727:, technical wording and abstract geological, metallurgical and economic information may not actually significantly advantage an investor who is not able to fully nor properly understand the content or importance of this information. In this way the NI 43–101 may not serve the interests of those it is designed to protect— the retail investors who may easily misinterpret such information.
592:
to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity.
583:
planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed.
573:
An inferred mineral resource is that part of a
Mineral Resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and reasonably assumed, but not verified, geological and grade continuity. The estimate is based on limited information and
555:
The block model is created using geostatistics and the geological data gathered through drilling of the prospective ore zone. The block model is essentially a set of specifically sized "blocks" in the shape of the mineralized orebody. Although the blocks all have the same size, the characteristics of
618:
A proven mineral reserve is the economically mineable part of a
Measured Mineral Resource demonstrated by at least a Preliminary Feasibility Study. This Study must include adequate information on mining, processing, metallurgical, economic, and other relevant factors that demonstrate, at the time of
591:
A measured mineral resource is that part of a
Mineral Resource for which quantity, grade or quality, densities, shape, and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters,
317:
Samples closer to the point of interest get a higher weighting than samples farther away. Samples closer to the point of estimation are more likely to be similar in grade. Such inverse distance techniques introduce issues such as sample search and declustering decisions, and cater for the estimation
627:
When the Bre-X Minerals ltd. scandal was revealed in the spring of 1997, it was one of the largest core salting scams in history and galvanised the development of the NI 43–101 reporting standards. While not the first (Tapin Copper salted samples in the 1970s), it is one of the most popular and the
564:
A mineral resource can be explained as a concentration or occurrence of diamonds, natural solid inorganic material, or natural solid fossilized organic material including base and precious metals, coal, and industrial minerals in or on the Earth's crust in such form and quantity and of such a grade
107:
model serves as the geological basis of all resource estimation, an orebody modeling project starts with a critical review of existing drill hole and surface or underground sample data as well as maps and plans with current geological interpretation. Drill hole and/or sample databases are set up to
719:
The promulgation of a codified reporting scheme makes it more difficult for fraud to occur and reassures investors that the projects have been assessed in a scientific and professional manner. However, even properly and professionally investigated mineral deposits are not necessarily economic, nor
127:
Once the geological modeling is completed, the geological envelopes are divided into block models. Subsequently, the estimation of these blocks is done from "composites" that are point measures of the grade of ore in the rock. Several different mathematical methods can be used to do the estimation
600:
A Mineral
Reserve is the economically mineable part of a Measured or Indicated Mineral Resource demonstrated by at least a Preliminary Feasibility Study. This Study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the
482:
Example of one-dimensional data interpolation by
Kriging, with confidence intervals. Squares indicate the location of the data. The Kriging interpolation, shown in red, runs along the means of the normally distributed confidence intervals shown in gray. The dashed curve shows a spline that while
582:
An indicated mineral resource is that part of a
Mineral Resource for which quantity, grade or quality, densities, shape and physical characteristics, can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine
609:
A probable mineral reserve is the economically mineable part of an
Indicated and, in some circumstances, a Measured Mineral Resource demonstrated by at least a Preliminary Feasibility Study. This Study must include adequate information on mining, processing, metallurgical, economic, and other
196:. Put simply, it's a diagram created by taking pairs of points that are close together and drawing a line that is equidistant between them and perpendicular to the line connecting them. That is, all points on the lines in the diagram are equidistant to the nearest two (or more) source points.
765:
The establishment and subsequent revisions of the NI 43 101 document by the
Ontario Securities Commission provides a framework to adhere to when writing the report. By establishing these standards, investors are able to have a more reliable and honest review of potential mineralized zones.
227:
Produces biased estimates of grade and tonnage above an ore waste cut-off. Which is called the volume variance relationship i.e. the variability of the grade distribution depends on the volume of samples. Large volume samples mean small variability whereas small volume samples mean large
565:
or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a mineral resource are known, estimated or interpreted from specific geological evidence and knowledge.
799:
Glacken, I. M., & Snowden, D. V. (2001). Mineral
Resource Estimation. In A. C. Edwards, Mineral Resource and Ore Reserve Estimation – The AusIMM Guide to Good Practice (pp. 189–198). Melbourne: The Australasian Institute of Mining and
183:
into regions based on distance to points in a specific subset of the plane. That set of points (called seeds, sites, or generators) is specified beforehand, and for each seed there is a corresponding region consisting of all points
248:
The simplest weighting function in common usage is based upon the inverse of the distance of the sample from the point to be estimated, usually raised to the second power, although higher or lower powers may be useful.
701:
is to ensure that misleading, erroneous or fraudulent information relating to mineral properties is not published and promoted to investors on the stock exchanges overseen by the
Canadian Securities Authority.
459:
of the intermediate values. Interpolating methods based on other criteria such as smoothness need not yield the most likely intermediate values. The method is widely used in the domain of
322:
140:
assigns grade values to blocks from the nearest sample point to the block. Closest sample gets a weight of one; all others get a weight of zero. In two dimensions, this method generates a
388:
601:
time of reporting, that economic extraction can be justified. A Mineral Reserve includes diluting materials and allowances for losses that may occur when the material is mined.
403:
Exponent gives flexibility. The same estimation procedure can be used to create very smooth estimates (like a moving average) or very variable estimates (like nearest neighbor)
312:
671:). Bre-X bought the Busang site in March 1993 and in October 1995 announced significant amounts of gold had been discovered, sending its stock price soaring. Originally a
853:
108:
suit all the quantitative and qualitative information necessary to build a resource model. The creation of a geological model may include the following steps:
775:
742:). All 3 codes are similar but not identical on requirements, definitions, and terminology. Regardless of the technicalities of each document, all exist to:
692:
842:
Den Tandt, M., & Howlett, K. (1997). Bre-X debacle may spawn new regulations OSC, TSE to examine juniors' reporting rules. The Globe and Mail.
739:
683:(TSE), with a total capitalization of over CAD $ 6 billion. Bre-X Minerals collapsed in 1997 after the gold samples were found to be a fraud.
660:
720:
does the presence of a NI 43-101-, JORC- or SAMREC and SAMVAL-compliant CPR or QPR necessarily mean that it is a good investment.
831:
821:
CIM Standing Committee on Reserve Definitions. (2010). CIM Definition Standards – For Mineral Resources and Mineral Reserves.
245:
applied, since it resorts to the inverse of the distance to each known point ("amount of proximity") when assigning weights.
574:
sampling gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.
503:. Krige sought to estimate the most likely distribution of gold based on samples from a few boreholes. The English verb is
780:
730:
Two main regulatory documents exist depending on the national jurisdiction the company is filed with. In Canada, the
734:
report details requirements of reporting mineralized findings. In Australia, the Joint Ore Reserves Committee Code (
54:
188:
to that seed than to any other. These regions are called Voronoi cells. The Voronoi diagram of a set of points is
899:
738:), and South Africa mandates the South African Code for the Reporting of Mineral Resources and Mineral Reserves (
456:
455:
chosen to optimize smoothness of the fitted values. Under suitable assumptions on the priors, Kriging gives the
17:
755:
Standardize for the disclosure of assay and drill results and procedures so that all data is clear to investors
137:
546:
Flexibility and power created by many parameters also create arbitrariness and more possibilities for error.
332:
610:
relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified.
889:
731:
698:
238:
77:
is used to determine and define the ore tonnage and grade of a geological deposit, from the developed
894:
884:
483:
smooth nevertheless departs significantly from the expected intermediate values given by those means.
255:
50:
45:
761:
Assign accountability to an individual deemed to be a competent person/ professional in the industry
809:
Srivastava, M. R. (2013). Geostatistics and Orebody Modelling. Toronto: FSS Canada Consultants Inc.
128:
depending on the desired degree of precision, quality and quantity of data and of their nature.
680:
193:
752:
Ensure periodic, independent reporting of reserves and review and approval of reserve reports
189:
832:
https://nationalpost.com/news/story.html?id=d5d283b0-d10d-4e23-8c91-3fd20bf1831e&k=24530
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8:
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830:"Long-awaited Bre-X court decision due Tuesday" National Post and Calgary Herald
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Similarly, the publication of a complex technical report with all the inherent
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scandal to protect investors from unsubstantiated mineral project disclosures.
492:
487:
The theoretical basis for the method was developed by the French mathematician
468:
118:
Geostatistical analysis, variographic analysis of composite spatial continuity
878:
496:
440:
436:
242:
159:
500:
321:
32:
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495:, the pioneering plotter of distance-weighted average gold grades at the
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each with a unique grade; in three dimensions this method generates a
664:
652:
467:. The technique is also known as Wiener–Kolmogorov prediction, after
153:
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145:
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Standardize definitions of reserve types and reserve calculations
648:
104:
735:
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Inverse distance interpolation for different power parameters
713:
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of blocks of a defined size, in addition to point estimates.
656:
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Regulate ways of making sure samples are not tampered with
530:
Statistical approach allows uncertainty to be quantified.
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Creation, standardization and validation of the database.
439:, Kriging or Gaussian process regression is a method of
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Valuation (finance) § Valuation of mining projects
655:
scandal when it reported it was sitting on an enormous
776:
United Nations Framework Classification for Resources
693:
United Nations Framework Classification for Resources
335:
258:
88:
Section plotting and interactive geological modeling.
232:
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Set criteria for approval of assay labs and methods
686:
515:, following the pronunciation of the name "Krige".
443:for which the interpolated values are modeled by a
115:
Sectional, longitudinal, 3D and multi-seam modeling
619:reporting, that economic extraction is justified.
382:
306:
163:20 points and their Voronoi cells (larger version
876:
413:Preferential sampling makes estimates unreliable
543:Computationally intensive: hardware, software.
527:Geological knowledge is captured in variogram.
419:Extremes create large halos of great estimates
854:"The $ 6 Billion Gold Mine That Wasn't There"
836:
679:$ 286.50 (split adjusted) in May 1996 on the
851:
422:Choice of exponent introduces arbitrariness
131:
803:
122:
78:
524:Very good in local and global estimates.
477:
416:Requires decision on which sample to use
320:
158:
550:
451:, as opposed to a piecewise-polynomial
329:, from scattered points on the surface
98:
14:
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224:Local discontinuities are unrealistic
214:When automated, reasonably fast in 2D
852:Grundhauser, Eric (21 August 2015).
705:The NI 43–101 was created after the
675:, its stock price reached a peak at
559:
383:{\displaystyle z=\exp(-x^{2}-y^{2})}
211:Easy to use as a repeatable standard
94:Block modeling and block estimation.
26:
595:
511:; both are often pronounced with a
24:
812:
112:Computer-based 3D orebody modeling
25:
911:
239:inverse distance weighting method
233:Inverse distance weighting method
164:
697:Plainly put, the purpose of the
687:Emergence of reporting standards
491:based on the Master's thesis of
31:
628:catalyst for reporting reform.
622:
457:best linear unbiased prediction
307:{\displaystyle w_{i}=\left^{p}}
845:
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643:. A major part of the group,
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1:
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639:was a group of companies in
507:and the most common noun is
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75:Mineral resource estimation
44:to comply with Knowledge's
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732:National Instrument 43-101
699:National Instrument 43-101
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651:, was involved in a major
578:Indicated Mineral Resource
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208:Easy to calculate manually
156:each with a unique grade.
587:Measured Mineral Resource
569:Inferred Mineral Resource
631:
605:Probable Mineral Reserve
91:Geostatistical analysis.
57:may contain suggestions.
42:may need to be rewritten
712:"The gold reserves at (
540:Not easy to comprehend.
241:" was motivated by the
138:nearest neighbor method
132:Nearest neighbor method
900:Management cybernetics
681:Toronto Stock Exchange
614:Proven Mineral Reserve
484:
400:Computationally simple
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194:Delaunay triangulation
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123:Block model estimation
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551:Resource block model
465:computer experiments
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99:Geological modelling
645:Bre-X Minerals Ltd.
485:
447:governed by prior
392:
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205:Easy to understand
171:In mathematics, a
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890:Mineral economics
560:Mineral resources
473:Andrey Kolmogorov
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72:
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46:quality standards
16:(Redirected from
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895:Geology software
885:Economic geology
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445:Gaussian process
435:, originally in
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63:December 2020
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861:. Retrieved
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51:You can help
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800:Metallurgy.
673:penny stock
659:deposit at
653:gold mining
449:covariances
79:block model
879:Categories
787:References
691:See also:
519:Advantages
433:statistics
395:Advantages
237:The name "
200:Advantages
736:JORC Code
665:Indonesia
647:based in
365:−
352:−
346:
154:polyhedra
55:talk page
770:See also
513:hard "g"
505:to krige
146:polygons
649:Calgary
509:Kriging
427:Kriging
192:to its
105:orebody
740:SAMREC
725:jargon
669:Borneo
661:Busang
641:Canada
453:spline
186:closer
53:. The
858:Slate
714:Bre-X
707:Bre-X
637:Bre-X
632:Bre-X
181:plane
179:of a
175:is a
165:below
865:2015
667:(in
657:gold
471:and
463:and
190:dual
136:The
677:CAD
431:In
343:exp
103:An
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867:.
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369:y
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