Mineral Resource Estimation Methodology
Defining Diatomite Resources as a "Performance Mineral"
Diatomite for filter-aid or filler uses is informally classified as a "performance mineral", ie a mineral in which the physical attributes of a mineral material perform specific functions (e.g. filtering, specialty fillers, anti-blocking agents) of economic value, and chemical content is of concern principally as a deleterious contaminant.
Quality parameters (in contrast to chemical content or grade) cannot be statistically treated to yield answers on finished product characteristics. That can only be established by experimentation and performance testing methods.
Chemical and physical testing of crude diatomite establishes basically how the material should be processed. an intermediate product (degritted diatomite) must be produced as well as final calcined and flux-calcined products to test to establish fully its commercial potential. A degritted diatomite determined to have commercial value may be up-graded from an intermediate product to a "natural diatomite product"
Mineral Resources Estimation Methodology
Mineral Resources Defined - That diatomite occurring in mineable beds determined by filtration flow-rate and broad physical and chemical characterisation testing to be acceptable as blendable raw material for the Badgingarra diatomite processing plant.
Determination of Volume - Mineral Resources of the Badgingarra deposit were estimated manually through a polygonal method to determine the volume of each bed within a specific area of influence of test-pits and drill-holes, designated as a "resource block". Useable thickness of diatomite (within the total bed thickness) were determined for individual beds A, B, C and AB for each reference test-pit or drill-hole where they occur.
Earlier Studies on Hudson Western Australian Diatomite (DE)
Government Chemical Laboratory Study
The Government Chemical Laboratory performed pilot-scale tests on bulk samples from layers of the Badgingarra Western Australian diatomite deposit in 1978 and concluded that the material was suitable for many Australian filter-aid and filler applications
Kieselguhr de Mexico, S.A. Investigation
Kieselguhr de Mexico, S.A. (Kieselguhr) performed extensive testing on Western Australian Hudson diatomite (DE) samples during 1973-79.
Kieselguhr concluded that material from the Badgingarra Western Australian diatomite deposit was excellent quality for their plant process and was superior in grade to most other regional occurrences for applications, such as beer and wine filtering. At that time, abundant file material is available on the Kieselguhr testing of materials from the Badgingarra and other Hudson Western Australian diatomite
Manville Reserve Study
The Manville Corporation conducted a joint study of the Badgingarra, Dongara and other Western Australian Hudson diatomite (DE) deposits during 1983-85, concluding that the Badgingarra Western Australian diatomite (DE) deposit was the most promising of the chain of the shallow lake occurrences.
The Manville study included the digging of at least 17 trenches, 5 of which were deepened further by drilling, and the auger-drilling of 45 shallow holes to define the edge of the deposit. Samples were collected of selected intervals int he test--pit walls and from the auger cuttings and tested for filtration and other properties.
Testing of samples from the channel and drill-hole samples by Manville produced a physical and chemical characterisation of the diatomite (DE) deposit in their summary report.
AFMECO Study
AFMECO, the Australian branch of the French mineral producer COGEMA, investigated the Badgingarra Western Australian diatomite (DE) deposit about 1986 and concluded that it was the most promising diatomite occurrence in Western australia.
Based on a study of the Manville data, very limited geological observation and sampling, and some verification testing in French laboratories, AFMECO concluded that the upper three layers offered economic potential
Kaiser Engineers/ Kidman & Associates Phase
Kidman & Associates conducted extensive drilling, sampling and testing work on the Badgingarra Western Australian diatomite (DE) deposit during December 1992 - August 1993, resulting in the preparation of a Measured Resource Study.
Initially, selected Manville test-pits as well as new test-pits were resampled or sampled with the objective of correlating data from the Manville Program to allow preparation of a Provent Ore Reserve Estimate from the Manville work. Kidman continued on with a fresh drilling program and investigation of possible processing methods to upgrade clayey diatomite.
The Australian diatomite (DE) deposit was drilled on 50 metre centres by rotary air-blast (RAB) drilling, and testing carried out on a 100-metre spacing within this grid. Extensive drilling sample tests work was conducted at Normet Laboratories and this drilling program defined the base of the diatomaceous earth (DE) sediments in the basin
Technical Studies on Badgingarra Diatomite Deposit
Extracted from Mineral Resource Statement, Holmes Reserves LTD, 13 April 1993
Technical studies of the Badgingarra deposit showing significant commercial potential include:
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Government Chemical Laboratory (1978)
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Kieselguhr de Mexico, S.A. (1978 - 79)
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Manville Corporation (1983 - 85)
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AFMECO (Australian subsidiary of COGEMA) 1986
Voluminous technical material and diatomite investigations on the chain of shallow lacustrine deposits in the region. From trenching and sampling work, some bulk samples produced favourable results when tested at Australian breweries concluding that the deposits were suitable as sources for filter-aid diatomite and offered economic potential.
Celite products Filtercel, Standard Supercel and Hyflo Supercel were used during the Manville-Mallina joint study in 1983-85 as comparative product standards against which the Badgingarra sample analyses could be compared.
HUDSON DIATOMACEOUS EARTH (DE)
BADGINGARRA
DIATOMACEOUS EARTH (DE)
PROJECT
M70/129 & M70/361
Stockpile: 20,000 tonnes DE
Inferred resource:1.3 million tonnes DE
Surveyed area: 96 ha
HUDSON DIATOMACEOUS EARTH
Hudson Diatomaceous Earth (DE) Mining Projects
Further testwork on Badgingarra Diatomaceous earth during 1988-93 included 20 calcination tests at laboratory scale and two pilot-scale rotary-kiln trials.
Calcined and flux-calcined products of commercial grade were consistently made through these test periods (Chemistry Centre, W.A. 1990)
1988-93
Filter Aid & Filter products:
Previous Investigations
Eight test programmes on Badgingarra diatomite have been carried out through the Chemistry Centre of Western Australia.
Four investigations were conducted, which included 41 flux calcination tests on Badgingarra Diatomaceous earth samples beneficiated at laboratory scale and five pilot-scale rotary-kiln to produce bulk quantities of calcined diatomite.
1979-80
Drilling and test-pitting
Rotary Air Blast Drill Holes
9 Rotary Air Blast (RAB) holes were drilled on the Badgingarra deposit on 29-30 September 1993 to obtain fresh samples and to determine the reliability of the RAB hole drilling method. It was performed under the supervision of Energy Geotech Consultants Pty Ltd at the direction of D.A. Holmes
Filtration/Characterisation Test holes
28 test pits were dug on a rectangular grid over an area of 3000 metres by 400 metres using a back-hoe to depths up to 3 metres or as deep as flooding in the hole would allow.
20 of these pits were excavated at 100 metre centres for basic reserve calculation and blending purposes.
The remaining 8 test pits were excavated at 50 metre centres between the basic pits to assess material variability.
The intention of this test-pitting was to obtain fresh channel samples from the pit walls to support further testing and to allow geologic observation of the upper layers in the diatomaceous sediment section.
Drill hole or test pit spacing at most diatomite mines around the world is within the range of 100 to 300 metres for resoource/reserve estimation.
Microscopic examination of Diatoms
Frederic L. Kadey Jr., internationally recognised expert on diatom identification and commercial diatomite occurrence, visited the Badgingarra site on 2 March 1994 to observe the stratigraphy of the deposit and to collect fresh samples of diatomite from exposed pit walls.
Overall, Kadey concluded that:
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The diatoms occurring in the Badgingarra deposit vary little between beds and the diatom assemblages vary little across the deposit, based on limited microscopic study on samples collected from the KP test-pits.
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The predominant diatom type is a very fine grained, acicular form apparently well suited for slow flow filter-aid products and some filler applications
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Coarse-grained diatoms show little breakage or fragmentation. The fine rained, acicular diatoms show greater brakage, but acted as effective filter aids in filtration flow rate testing
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Flux-calcining will require use of 3 to 6% sodium carbonate to make a broad flow rate range of filter-aid products
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Unmilled aggregate (platy material) comprises the principal contaminant in the crude diatomite and consists of weakly silica cemented diatomite. Quatz comprises less than 5% of the crude diatomite overall.
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Samples tested for filtration flow rate during the Kaiser Engineers program generally contained execssive fines, and will yield more favourable test results when classified into finished products.
Kadey conducted microscopic examinations of the Badgingarra samples in Jurien and subsequently in Perth during 4-11 Mach 1994 to identify the diatom types and assemblage characterise the material in crude, degritted and flux-calcined forms, and establish its relevance to potential commercial diatomites.
In his examinations, Kadey typically noted:
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Diatom assemblage and approximate percentage of each diatom genus
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Diatom general
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Degree of fragmentation or damage to diatom
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Presence and nature of contaminants
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Size and shape of diatoms
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Degree of clumping in flux-calcined samples.
Testing program
Summary of testing performed for Kaiser Engineers at the direction of Holmes Reserves Ltd during September 1993 to March 1994.
For table results of the testing program:
Filtration Flow-rate testing
Normet Laboratories performed filtration flow-rate tests on 54 samples and composited samples from selected intervals during November 1993-February 1994. This testwork included degritting, glux calcination in a muffle furnace and filter testing of both natural and calcined diatomite products. The filtration tests employed a Grefco bomb filtration testing device and the test results were compared to control samples of Celite Filtercel and Hyflo products. Most samples were analysed in triplicate, a few duplicate.
Filtration flow rate testing was performed in three individual phases:
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6 composited samples were tested during the Stage 1 - Characterisation and Blending Study described int eh following text from 6 representative panels of the Central Zone area
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28 samples were analysed from selected intervals in 14 test pits in Stage 1 work
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20 samples were analysed from selected intervals in 8 test pits to complete filtration testing coverage in early Stage 2 work
Characterisation Testing
Conducted during November 1993 to:
1. measure and characterise the crude diatomite of the top 2 to 3 metres of the Badgingarra deposit and
2. to identify and characterise the flux-calcined products which could be made by blending and flux-calcining composited test-pit samples.
Overall, this preliminary study characterised the physical and chemical properties of the flux-calcined filter aid and filler products, subject to additional testing in Stage 2. It established that the upper layer Badgingarra raw materials are generally acceptable in filtration rate, chemical content, loss on ignition and pH and perpheral in brightness, wet density, loose weight and resistivity, for the production of slow flow filter-aid products and fillter by-product.
The peripheral physical characteristics noted herein are likely to be improved by more efficient processing at the pilot plant level or in actual production.
Badgingarra Deposit
The Badgingarra deposit (also known as the "Hill River") has significant potential.
Exploration and testing by leading mining companies and laboratories over more than two decades have well documented its diatomite geology and quality.
During 1993-94, Hudson investigations directed towards development of the deposit as a raw material source for a plant producing filter-aid and filler products.
Badgingarra Diatomaceous Earth Deposit
- classic fresh-water shallow lacustrine diatomite deposit
- the largest in a chain of similar small deposits occurring west of the Darling escarpment between Perth and Dongara, W.A.
Nearly circular in outline with a diameter of about 650 metres.
In cross-section, it is saucer shaped and reaches an inferred maximum thickness of about 20 metres, based on earlier trenching and drilling.
Deposit located in a shallow depression about 17km Northwest of Badgingarra within the Shire of Dandaragan and 230 km North by road of the city of Perth in WA.
Intensive sampling and testing of the upper three metres (beds A, B, C and AB) of the Badgingarra deposit have identified Measured and Indicated Resources diatomite deposit suitable as filter-aid raw materials, to produce filter-aid products for use by the brewing and other industries, with filler by-products available for Australian and export markets.
Lab testing of test-pit samples has yielded filtration flow rate results consistently in the Celite Filtercel to Hyflo Supercel product range. Some exploratory samples have produced flow rates in excess of Hyflo.
Identified Mineral Resources in the upper layers of the Badgingarra deposit are estimated mostly from test-pitting and sampling program, with some geological and chemical information taken from earlier Mallina (formerly Hudson Resources) testing programs. This consist of the diatomite occurring in mineable A, B, C or AB beds determined by filtration flow-rate and broad physical and chemical characterisation testing to be acceptable as blendable raw material. Identified Mineral Resources of the Central Zone, which covers the principal test pitting grid on the deposit and the Peripheral Zone, which extends to the edge of the mineable deposit, include a Measured Resource of 242,100 tonnes in the Central Zone and Indicated Resource of 89,100 tonnes in the Peripheral Zone.
Drilling programs conducted by Manville and Kidman both intersected deeper resource, which are estimated to include Inferred Resources of 240,000 tonnes and Pre-Resource Mineralisation of 260,000 tonnes of in-situ diatomite and clayey diatomite.
Holmes Reserves Ltd developed a two stage program to lead the program to a final Ore Reserve Estimate:
Stage 1 - Characterisation and Blending Study: preliminary pitting and testing program to establish the overall physical and chhemical characteristics of the deposit and the feasibility of developing a blending program for raw material supply.
Stage 2 - Bulk Sampling and Product Development Study: on-going program to take representative bulk samples of the upper layers through processing steps that will identify the products that can be made and their recovery rates, and to supply finished product samples for potential end-user testing.
The Badgingarra deposit is a fresh-water deposit located about 200km north of Perth, Western Australia, close to rail and highway transportation. Earlier drilling has revealed that the deposit may be as thick as 20 metres. The deeper diatomite layers lie below the water-table but may be recoverable for swimming pool filter-aid and various absorbent products applications.
Diatom study by F.L. Kadey, Jr. internationally recognised expert on the economic geology of diatomite, indicates that diatom assemblages are consistent across the deposit and that the diatom species present appear favourable for commercial filteraid development.
Selective blending of the diatomites forming the upper layers of the Badgingarra deposit narrows the physical and chemical variability of potential raw diatomite feed.
HOLMES RESERVES, LTD.
Industrial Mineral Consultants
Denver, Colorado, U.S.A
'Executive Summary ' of Mineral Resource Statement
The Badgingarra Diatomite Deposit Shire of Dandaragan Western Australia
April 1993