RIFT VALLEY RESOURCES AFRICA PTY LTD ASX code "RVY"
Board of Directors:
Geoff Gilmour
Managing Director
Greg Cunnold
Technical Director
Graeme Clatworthy Non-executive Director
Level 2/23 Barrack St
Perth
Tel +61 8 9221 00 90
Fax +61 8 9221 00 95
ABN 86 121 985 395
Rift Valley Resources Limited ("the Company") (ASX: RVY) is pleased to announce the results of the recently completed drilling programme at the Company's 70% owned Longonjo prospect in Angola. Highlights include: -• 4m composite assays up to 11.32% TREO
• All drill holes returned significant REE mineralisation from surface over an area 600m x 500m . (table 1)
• Mineralisation remains open in all directions and at depth
• Broad mineralised intercepts from surface including: -
39m @ 4.48% TREO from surface.
21m @ 5.33% TREO from surface.
32m @ 4.94% TREO from surface.
20m @ 6.75% TREO from surface.
• Located proximal to National highway, railway and grid power
• Mr Gavin Beer appointed as consultant to the company
Figure: 1 Drilling at Longonjo
The assay results pertaining to the first pass drilling programme initiated at Longonjo in January 2014 and completed during February 2014 have been returned. As previously announced (24 January 2014) the drilling aimed to test the bedrock mineralisation beneath a +0.5% REE soil anomaly some 3.5km long and 1.7km wide.(figure 4) The Rotary Air Blast (RAB) drilling was carried out to blade refusal on a nominal 100m x 100m, staggered grid pattern and has tested an area of approximately 600m x 500m. Drilling encountered significant rare earth mineralisation - in every hole (Table 1). Mineralisation remains open in every direction and at depth. A drill hole location plan illustrating the significant intersections is presented below.
Assay results relate to four metre composite samples compiled on site and submitted to Intertek (Walvis Bay - Namibia) for sample preparation with the resulting pulps sent to Genalysis (Perth - Australia) where analysis was carried out by way of fusion with an ICP-MS finish. The highest TREO composite result returned was 11.32%, detailed in the section below.
The Directors consider the initial Longonjo RAB drilling programme an unmitigated success. Whilst drilling has tested only a small portion of the soil anomaly the geochemistry has been qualified at depth with broad intersections of significant rare earth mineralisation over an area with sufficient potential to delineate substantial tonnages. The mineralisation occurs from surface and remains open in every direction as well as at depth. A 'fly through' is posted on the Rift Valley Resources website.
Link to fly through: www.riftvalleyresources.com.au
The Company considers the metallurgical assessment of Longonjo to be the next priority. To this end RVY has engaged the services of Gavin Beer, a consultant metallurgist who specialises in REE metallurgy and has worked on deposits for Arafura Resources, Peak Resources and Mkango Resources amongst others. Gavin has initiated a metallurgical characterisation test work programme. This work is aimed at:
1. Identifying if there is any natural size versus grade concentration that may aid ore beneficiation.
2. Assessing if magnetics may be used for the upgrading rare earth minerals.
3. Investigating the potential for gravity separation.
4. Conducting a mineralogy assessment.
The test work is scheduled to take 4 weeks, the results of which will be announced to the market as they come to hand.
The Longonjo REE prospect is located within the Ozango Project, approximately 600km southeast of the Angolan capital Luanda and 50km west of the regional city of Huambo. It is located proximal to good infrastructure including roads, towns and the recently recommissioned railway which links the area to the deep water Atlantic port of Lobito
The Ozango Project consists of a single Exploration Licence (009/01/07T.P/ANG-MGMI/2011) that covers a Large area of 3,670 square kilometres. The property extends for 100 kilometres in an east-west direction and varies between 28 to 46 kilometres in width. The northeast corner of the property comes to within 17 kilometres of Huambo.
The Project area covers some 3,670km2 of Archaean/Palaeoproterozoic greenstone rocks that have been intruded by Cretaceous felsic volcanics, carbonatites and kimberlites. These rocks are considered highly prospective for REE, phosphate, copper, iron ore and gold. To date, however, this area has seen very little modern exploration.
The Longonjo REE prospect is the first target within the Ozango Project to be drill tested by Rift Valley. Located near the town of Longonjo in the north-central portion of the Project area the prospect centres on a Cretaceous age, carbonatite intrusive. The geology is typical of REE mines and prospects globally including Lynas Corp's Mt Weld deposit in Western Australia and Peak Resources' Ngualla deposit in Tanzania.
A soil geochemical sampling program undertaken at Longonjo over an area of 8km2 defined a large and robust
3.5km long and 1.7km wide +0.5% REO anomaly which remains open to the west. A follow up trenching and pitting program carried out to test the bedrock within the soil anomaly returned highly encouraging results of up to 18.9% TREO from the pit bedrock samples. The drilling program aims to test the subsurface mineralization and will also provide sufficient sample for an initial metallurgical assessment to be carried out.
We advise in accordance with Australian Stock Exchange Limited Listing Rules 5(6) that the exploration results contained within this ASX Release is based on information compiled by Mr Greg Cunnold who is a member of the Australian Institute of
Mining and Metallurgy. Mr Cunnold is not an employee of Rift Valley Resources Ltd and has consented in writing to the inclusion in this ASX Release of matter based on the information so compiled by him in the form and context in which it
appears. Mr Cunnold has sufficient experience relevant to the style of mineralisation and type of deposit under consideration to be qualified as a Competent Person as defined by the 2004 Edition of the "Australian Code for reporting of Exploration Results,
Mineral Resources and Ore Reserves".
The information in this release that relates to Metallurgical Testwork is based on information compiled and / or reviewed by Mr
Gavin Beer who is a Member of The Australasian Institute of Mining and Metallurgy and a Chartered Professional. Mr Beer is
a Consulting Metallurgist with sufficient experience relevant to the activity which he is undertaking to be recognized as competent to compile and report such information. Mr Beer consents to the inclusion in the report of the matters based on his information in
the form and context in which it appears.
For further information please contact:
Geoff Gilmour
Managing Director
Rift Valley Resources Limited
Tel + 61 8 9430 9966
Fax + 61 8 9430 9965 info@riftvalleyresources.com.au
Depth | Depth To | Width | TREO | ||||
Hole ID | EASTING | NORTHING | RL | From (m) | (m) | (m) | (%) |
LJ001 | 524074 | 8570978 | 1567 | 0 | 39 | 39 | 4.48 |
LJ002 | 523978 | 8570970 | 1573 | 0 | 32 | 32 | 2.67 |
LJ003 | 524019 | 8570898 | 1588 | 0 | 20 | 20 | 2.56 |
LJ004 | 524113 | 8570896 | 1573 | 0 | 16 | 16 | 2.88 |
LJ005 | 524072 | 8570798 | 1569 | 0 | 32 | 32 | 1.42 |
LJ006 | 524172 | 8570804 | 1562 | 0 | 23 | 23 | 1.96 |
LJ007 | 524270 | 8570800 | 1563 | 0 | 24 | 24 | 1.87 |
LJ008 | 524323 | 8570700 | 1554 | 0 | 30 | 30 | 1.91 |
LJ009 | 524225 | 8570700 | 1557 | 0 | 21 | 21 | 5.33 |
LJ010 | 524362 | 8570820 | 1563 | 0 | 24 | 24 | 3.45 |
LJ011 | 524324 | 8570888 | 1564 | 0 | 20 | 20 | 3.66 |
LJ012 | 524228 | 8570890 | 1569 | 0 | 25 | 25 | 2.42 |
LJ013 | 524260 | 8571014 | 1577 | 0 | 32 | 32 | 4.94 |
LJ014 | 524167 | 8571000 | 1575 | 0 | 32 | 32 | 3.31 |
LJ015 | 524209 | 8571098 | 1582 | 0 | 20 | 20 | 2.25 |
LJ016 | 524121 | 8571106 | 1586 | 0 | 27 | 27 | 4.69 |
LJ017 | 524062 | 8571100 | 1590 | 0 | 22 | 22 | 3.63 |
LJ018 | 524091 | 8571200 | 1604 | 0 | 20 | 20 | 6.75 |
LJ019 | 523975 | 8571198 | 1593 | 0 | 35 | 35 | 3.18 |
LJ020 | 523866 | 8571170 | 1584 | 0 | 40 | 40 | 2.58 |
LJ021 | 523832 | 8571100 | 1567 | 0 | 20 | 20 | 2.10 |
LJ021 | 523832 | 8571100 | 1547 | 28 | 32 | 4 | 1.51 |
LJ022 | 523917 | 8571076 | 1573 | 0 | 36 | 36 | 2.95 |
Table 1
Note: Results are derived from 4 metre composite samples
Intersections calculated using a 1% lower cut, no upper cut and no internal dilution.
TREO% comprises of the following:
CeO2 | Cerium(IV) oxide |
Dy2O3 | Dysprosium oxide |
Er2O3 | Erbium Oxide |
Eu2O3 | Europium Oxide |
Gd2O3 | Gadolinium Oxide |
Ho2O3 | Holmium Oxide |
La2O3 | Lanthanum Oxide |
Lu2O3 | Lutetium Oxide |
Nd2O3 | Neodymium Oxide |
Pr6O11 | Praseodymium Oxide |
Sm2O3 | Samarium Oxide |
Tb4O7 | Terbium Oxide |
Tm2O3 | Thulium Oxide |
Y2O3 | Yttrium Oxide |
Yb2O3 | Ytterbium Oxide |
Criteria | JORC Code explanation | Commentary |
Sampling techniques | • Nature and quality of sampling (e.g. cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc). These examples should not be taken as limiting the broad meaning of sampling. | • 4m composite samples taken from 1m drill sample bags with a 450mm x 50mm PVC spear being pushed diagonally to the bottom of the sample bag. Average sample weights were 3-4kg. |
• Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used. | • Regular air and manual cleaning of cyclone to remove hung up clays. • Standards & replicate assays taken by the laboratory. | |
• Aspects of the determination of mineralisation that are Material to the Public Report. | • RAB chips were geologically logged over 1m intervals and sampled over 4m composite lengths from the surface. Depending on the hole depth, the maximum interval was 4, and minimum was 1m. Samples assayed for a suite of REE minerals as well at U, Th, P, Fe and Ca. | |
• In cases where 'industry standard' work has been done this would be relatively simple (e.g. 'reverse circulation drilling was used to obtain 1 m samples from which 3 kg was pulverised to produce a 30 g charge for fire assay'). In other cases more explanation may be required, such as where there is coarse gold that has inherent sampling problems. Unusual commodities or mineralisation types (e.g. submarine nodules) may warrant disclosure of detailed information. | • RAB drilling was used to obtain 1m samples from which 4m composite samples from which 3kg was pulverised to produce a 30g charge for fusion and ICP-MS analysis. | |
Drilling techniques | • Drill type (e.g. core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc) and details (e.g. core diameter, triple or standard tube, depth of diamond tails, face- sampling bit or other type, whether core is oriented and if so, by what method, etc). | • Rotary Air Blast with 4.5" blade drill bit. |
Drill sample recovery | • Method of recording and assessing core and chip sample recoveries and results assessed. • Measures taken to maximise sample recovery and ensure representative nature of the samples. • Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse material. | • RAB recovery and meterage was assessed by comparing drill cutting volumes (sample bags) for individual meters. Recoveries were recorded. Routine check for correct sample depths are undertaken every rod (3m). • RAB sample recoveries were visually checked for recovery, moisture and contamination. The cyclone was routinely cleaned ensuring no material build up. • Due to the good drilling conditions (dry, firm material) the geologist believes the samples are homogenous and representative. |
Logging | • Whether core and chip samples have been geologically and geotechnically logged to a level of detail to support appropriate Mineral Resource estimation, mining studies and metallurgical studies. • Whether logging is qualitative or quantitative in nature. Core (or costean, channel, etc) photography. | • Drill chip logging was completed on one metre intervals at the rig by the geologist. The log was made to Ocris logginmg software in detail. RAB drilling does not, however, support resource estimations. • Logging was qualitative in nature |
• The total length and percentage of the relevant intersections logged. • 100% of all meterages were geologically logged. |
Sub-sampling • If core, whether cut or sawn and • RAB samples were collected from the drill rig by techniques and whether quarter, half or all core spearing each collection bag and compiling a 4m sample taken. composite sample. Samples collected in mineralisation preparation • If non-core, whether riffled, tube were predominantly dry. Drill holes were terminated sampled, rotary split, etc and if the samples went wet. Wet samples were noted and whether sampled wet or dry. logged. • For all sample types, the nature, quality and appropriateness of the • The sample preparation followed industry best sample preparation technique. practice. Sample were oven dried followed by • Quality control procedures adopted pulverization of the entire sample in an LM5 or for all sub-sampling stages to equivalent pulverising mill to a grind size of 85% maximise representivity of samples. passing 75 micron. • Measures taken to ensure that the sampling is representative of the in • At this stage of the exploration, field QC involves the situ material collected, including for review of laboratory supplied certified reference instance results for field material, in house controls, blanks, splits and duplicate/second-half sampling. duplicates. These QC results are reported by the • Whether sample sizes are laboratory with final assay results. appropriate to the grain size of the material being sampled. • No field duplicates were taken. It is envisaged that 1m resplits of mineralised intervals will better validate the 4m composite results. • The sample sizes are considered more than adequate to ensure that there are no particle size effects. |
Quality of assay • The nature, quality and • The fusion digest is a complete digest and is the best data and appropriateness of the assaying and available for the ICP-MS finsh. Checks against a 4 acid laboratory tests laboratory procedures used and (hydrofluoric, nitric, perchloric and hydrochloric acids) whether the technique is considered will be carried out on the puls as a check. partial or total. • For geophysical tools, spectrometers, handheld XRF • Laboratory No geophysical or portable analysis tools instruments, etc, the parameters were used to determine assay values stored in the used in determining the analysis database. Handheld XRF machine was only used as a including instrument make and guide while drilling and readings have not been model, reading times, calibrations included in review of the data. Assay data only is used. factors applied and their derivation, etc. • Nature of quality control procedures • QC results (blanks, duplicates, standards) were in line adopted (e.g. standards, blanks, with commercial procedures, reproducibility and duplicates, external laboratory accuracy. Aqua regia digestion was used. checks) and whether acceptable levels of accuracy (ie lack of bias) and precision have been established. |
Verification of • The verification of significant • Work was supervised by the Technical Director sampling and intersections by either independent experienced in metals assaying. QC data reports assaying or alternative company personnel. confirm the sample quality are methodology. • The use of twinned holes. • No twin holes undertaken • Documentation of primary data, • Data storage as micromine files on company PC in data entry procedures, data Perth office verification, data storage (physical • No adjustments to the assay data have been made. and electronic) protocols. • Discuss any adjustment to assay data. |
Location of data • Accuracy and quality of surveys used • All drill collar locations were surveyed using a hand points to locate drill holes (collar and held GPS, accurate to within 3-5m. Holes were drilled down-hole surveys), trenches, mine on an approximate 100m x 100m grid. The area was workings and other locations used in The grid system used is WGS84 Zone 338. All reported Mineral Resource estimation. coordinates are referenced to this grid. The • Specification of the grid system topography was flat. used. • Quality and adequacy of topographic control. • Topography was fairly flat, small differences in elevation between drillholes will have little effect on |
mineralisation widths on initial interpretation. | ||
Data spacing and distribution | • Data spacing for reporting of Exploration Results. • Whether the data spacing and distribution is sufficient to establish the degree of geological and grade continuity appropriate for the Mineral Resource and Ore Reserve estimation procedure(s) and classifications applied. • Whether sample compositing has been applied. | • A nominal 100m x 100m drill patter to an average depth of 30-40m. • No new resource has yet been calculated. Previous resource calculation was completed in 2011. • Yes, as detailed previously. |
Orientation of data in relation to geological structure | • Whether the orientation of sampling achieves unbiased sampling of possible structures and the extent to which this is known, considering the deposit type. • If the relationship between the drilling orientation and the orientation of key mineralised structures is considered to have introduced a sampling bias, this should be assessed and reported if material. | • No, drilling vertical holes is routine in this style of mineralisation. Unbiased sample was achieved. The deposit type is well known. • The mineralisation is demonstrably disseminated throughout the host rock. There is no mineralised structure introducing a sample bias. |
Sample security | • The measures taken to ensure sample security. | • Sample security is managed by the Company. After preparation in the field samples are packed into polyweave bags and dispatched to the laboratory. All bags were transported by the Company directly to the assay laboratory. The assay laboratory audits the samples on arrival and reports any discrepancies back to the Company. No such discrepancies occurred. |
Audits or reviews | • The results of any audits or reviews of sampling techniques and data. | • No review of the sampling techniques has been carried out. The database is compiled by an independent contractor and is considered by the Company to be of sufficient quality to support the results reported. In addition, from time to time, the Company carries out its own internal data audits. |
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