Posts Tagged REE

Advances in Airborne and Ground Geophysical Methods for Uranium Exploration

Posted by on Tuesday, 30 April, 2013

IAEA (International Atomic Energy Agency) has published a book “Advances in Airborne and Ground Geophysical Methods for Uranium Exploration”.

“Due to growing global energy demand, many countries have seen a rise in uranium exploration activities in the past few years, and newly designed geophysical instruments and their application in uranium exploration are contributing to an increased probability of successful discoveries. This publication highlights advances in airborne and ground geophysical techniques and methods for uranium exploration, succinctly describing modern geophysical methods and demonstrating their application with examples.”

Download..


Radiometric and magnetic survey for REE

Posted by on Saturday, 15 October, 2011

Arctic Star Exploration Corp. announces that Aeroquest International Ltd. has completed airborne magnetic and radiometric surveys on three properties located in the Carbo area of ‘The Rocky Mountain Rare Metal Belt’ of northern British Columbia.

The Cap, Seebach and Javorsky rare earth element (“REE”) and rare metal properties are all located within the immediate vicinity of Spectrum Mining Corporation’s Wicheeda REE Discovery as well as the Carbo Project which has been drilled by Canadian International Minerals Inc. Arctic Star is conducting exploration under its option to earn up to 100% interest in these properties. The group of claims are located 80 km northeast of Prince George and together comprises 20 mineral claims covering approximately 9,129 hectares, making it one of the largest land positions in the camp.

The heli-borne AeroMAG magnetic gradient and radiometric survey consisted of approximately 1,500 line kilometres on the three properties. The preliminary results of the survey have identified several radiometric anomalies on the Cap property, which are considered to be high priority with respect to the other surveyed properties in the Carbo area. The magnetic component of the survey further defined the strong magnetic anomaly as previously defined by the regional magnetic survey.

The preliminary results of the airborne survey, in combination with the 2010 prospecting program which located outcrops of syenite with anomalous values of Nb and Zr (see November 17th News Release) are very encouraging. In the Carbo area, syenite is often found in close proximity to REE bearing carbonatite.

A detailed mapping and prospecting program, in combination with soil sampling has commenced on the Cap Property in order to verify the geophysical anomalies and define drill targets.

Publicly available records show that the nearby Wicheeda REE Discovery owned by Spectrum Mining showed encouraging results for REE in 2008 and 2009 drilling.

Source: http://www.marketwire.com/press-release/Arctic-Star-Exploration-Corp-Announces-Airborne-Surveys-Completed-TSX-V-ADD-1573392.htm


2011 exploration program on the Athabasca Basin with HTEM

Posted by on Thursday, 3 February, 2011

Kirrin Resources Inc.  announced plans for its 2011 exploration program.

The Key Lake Southwest (‘Key Lake SW’) uranium property located on the southeastern margin of the Athabasca Basin in Saskatchewan will attract an estimated budget of $0.7 million. Later this month, Kirrin will commence a 1,400 line km. helicopter-borne time domain electromagnetic geophysical survey. Following the interpretation of results, Kirrin is planning a program of summer fieldwork with the objective of finalizing the selection of drill sites.

The eastern margin of the Athabasca Basin in Saskatchewan, Canada, is home to the most productive uranium mines in the world, with roughly 25% of global uranium production coming from this area. Kirrin’s target at Key Lake SW is basement-hosted unconformity-type uranium, similar to Cameco’s basement-hosted Millennium deposit, located about 50 km to the north-northeast, the Phoenix discovery, located about 60 km northeast, and the former Key Lake mine located about 35 km east-northeast. The review of the technical disclosures regarding the recent Phoenix Discovery has revealed many geological similarities between Phoenix and Key Lake SW.

The interpretation of the recent 1,076 line-kilometre magnetic-electromagnetic (EM) airborne survey revealed 19 anomalies for follow-up, 7 of which are first priority. This follow-up will form the basis of the 2011 drilling campaign. Highway 914, which extends from Lac La Ronge to Key Lake, passes less than 2 km from the eastern edge of the property.

Exploration on March 2010 acquisition commenced in April 2010 with a 1,076 line-kilometre magnetic-electromagnetic (EM) airborne survey. The airborne survey utilised Fugro’s fixed-wing Tempest(r) Digital Time Domain Electromagnetic (DTDEM) system which provides maximum quantitative discrimination of relatively near surface (upper 200 to 300 m) conductivity variations.

Airborne magnetic surveys map the variation in magnetic susceptibility, which predominantly results from changes in the percentage of magnetite and some other magnetic minerals in the bedrock. The magnetic variations thus allow the mapping of differing lithologies, faults, potential alteration zones, etc. DTDEM surveys map the three-dimensional variation in conductivity that is caused by one or more of mineralogy (e.g., conductive minerals such as graphite or sulphides), intensity of alteration, water content or changes in salinity. The correlation of the magnetic responses with the EM conductive trends enables the indirect geological mapping of bedrock under overburden and possible Athabasca Basin sandstone outliers. As well, the airborne geophysical data can identify anomalies and potential geological targets that may be spatially associated with uranium deposits or alteration zones near such deposits.

Following the satisfactory results from December’s geophysical interpretation program at the Grevet REE project in northwestern Quebec, Kirrin is planning a three phase exploration season commencing in late April. The first phase will complete prospecting on priority areas, including the collection of samples and assessment of exploration potential. The second phase will primarily identify drill targets and will commence in July. The third phase, commencing in September-October, will be determined by the compilation and interpretation of the results obtained from the earlier 2011 phases and will likely comprise a 1,500 to 2,500 m drill program in 15 to 25 holes.


Interpretation of geophysical data for REE project in Quebec

Posted by on Thursday, 27 January, 2011

Kirrin Resources Inc.  announces the results of December’s geophysical interpretation program at its Grevet REE project in northwestern Quebec. The program met its objectives in confirming the relationship between magnetic signatures and magnetite-bearing carbonatite showings at Grevet and these interpretative results will assist in focusing the 2011 exploration program.

Commenting on the results, Kirrin President and CEO, Derek J Moran said: “The results of the geophysical interpretation have contributed to our understanding of the geology at Grevet. They have confirmed the relationship between magnetic signatures and the carbonatite and carbonatite-magnetite showings. Importantly, the geophysical interpretation has identified 15 key targets for follow-up during the 2011 Grevet exploration program.”

The geophysical program comprised geophysical interpretation of the ground magnetic data from the 2001, 2002 and 2010 surveys. In particular, the geophysical interpretation included a detailed examination of magnetic profiles in conjunction with known carbonatite and magnetite-carbonatite showings at Grevet. The intent was to define the trends of magnetic carbonatite and other magnetite-bearing rocks, and, especially, search for larger continuous potentially REE-bearing blind carbonatite bodies. In addition, integration of historic exploration and other geological data with the geophysical interpretation of the ground magnetic data has refined target selection and defined the specific follow-up program of work at selected targets in 2011.

The results and conclusions of the geophysical interpretation may be summarized as follows:


--  The merged, edited, then interpreted magnetic data resulted in a more
    coherent magnetic map of the Grevet REE property.
 --  Two major magnetic domains were outlined: Domain A, which is towards the
    northeast of the property and covers the mafic and ultramafic rocks; and
    Domain B, which is immediately adjacent and to the southwest and is over
    the felsic to intermediate composition volcanic rocks.
 --  Based on the magnetic evidence, numerous interpreted, dominantly
    northeast and north-northeast striking shear zones and/or brittle faults
    were outlined.
 --  The interpretation established, in large part, a relationship between
    magnetic signatures and the carbonatite and carbonatite-magnetite
    showings. Specifically, 52% of the carbonatite showings and 67% of the
    carbonatite+magnetite showings are associated with recognizable magnetic
    signatures derived from the ground magnetic survey data.
 --  Lastly, the interpretation identified 15 targets for follow-up during
    the 2011 exploration program.

The geophysical interpretation was prepared by Savaria Geophysics Inc.

Kirrin also announced that its Board of Directors has granted options over 1,755,000 common shares at an exercise price of $0.13 per share to nine directors, employees and consultants (closing price on January 26, 2011 was $0.13 per share). The expiry date is January 27, 2016 and one quarter of the options will vest annually. Included in the option award is a grant over 60,000 common shares at an exercise price of $0.13 per share to an IR consultant. Kirrin now has 3,046,000 options outstanding under its Option Plan, at an average exercise price of $0.13 per share.

Geology

The region about the Grevet property is primarily underlain by volcanic, sedimentary and igneous granitoid rocks of the Superior Geological Province. These are locally intruded by Proterozoic diabase dykes. The Archean rocks regionally have been affected by four regional deformation events, although within the Grevet property only two are readily evident. The Grevet property is mainly underlain by Archean basaltic and andesitic volcanic rocks that are cut, in places, by small northwesterly trending Archean gabbros and by carbonatite intrusions which are of uncertain, but probably Archean, age. The Archean rocks are cut north of the property by the southeast-trending Cameron Deformation Zone, which is a regional structural discontinuity, and to the south by the northeast-trending Wedding-Opawica brittle fault.

The carbonatite is particularly important because in places there are closely spaced magnetite veinlets and carbonatite dykelets, several of which carry highly anomalous concentrations of LREO up to at least 5.9%. Dr. D. Lentz, a consultant to Kirrin Resources, has looked at the existing geological and geochemical data for Grevet, and has suggested that because of the ferroan carbonatite association with magnetite, the Grevet REE property may have some geological similarities to the large Bayan Obo REE-bearing carbonatitic body in inner Mongolia. Bayan Obo is the world’s largest REE deposit, containing about 70% of the world’s known REE reserves.
Additional information relating to Kirrin is available on Kirrin’s web site at www.kirrinresources.com and on SEDAR at www.sedar.com.


Magnetic, VLF and radiometrics for REE

Posted by on Friday, 21 January, 2011

Silver Spruce Resources Inc. announces further results from ground geophysical surveys carried out on the 100% owned Pope’s Hill (PH) REE property located on the Trans Labrador Highway (TLH) in south central Labrador. The 73 line km geophysical survey of magnetics, VLF-EM and limited radiometrics was carried out in December under contract by Abitibi Geophysics of St Johns, Newfoundland. The surveys were focused on the original 62 claim block, which covers a 5 kilometer long trend of rare earth mineralization located in bedrock and angular boulders along and just to the north of the TLH. The surveys included GPS controlled magnetics, with readings taken every 2 seconds, VLF-EM with readings at 12.5 meter spacing and radiometrics, also at 12.5 meter spacing, over selected areas, covering some of the magnetic and electromagnetic anomalies located (see news release dated Dec. 30, 2010). The radiometric survey was limited in extent due to inclimate weather and was further hampered by snow cover which can affect the readings. The survey covered two small areas (4 lines) at 200 m intervals in the area of the bedrock pit and an area further to the east (2 lines) at 200 m intervals, which extended from the highway to the Pinus river to the north. The rare earth mineralization is variably non magnetic to magnetic and is associated with thorium/uranium making the samples radioactive and therefore responsive to radiometric surveys. The REE mineralization also appears to be shear hosted and the shear systems appear to respond to the VLF-EM survey.

The magnetics and VLF-EM show a number of linear magnetic anomalies, both positive and negative, crossing the property in an ENE direction. A number of the VLF-EM anomalies are coincident with, or marginal to, the magnetic highs with others in the magnetic low areas. A VLF-EM anomaly, between magnetic high zones, possibly indicating a shear system, occurs coincident with the anomalous REE samples in the bedrock aggregate pit on the side of the TLH and extends along strike to the east and west. The radiometric survey over this area shows a relatively strong, 1,000-1,500 total counts per minute (tcpm) and thorium anomaly coincident with the pit area and coincident VLF-EM anomaly which extends to the east and west along strike, over a 100 m plus strike length, and which is open to the west. Radiometric anomalies of 500 to > 1000 tcpm over background were also located in the central part of the grid, approximately 2 km to the east of the pit. No follow up has been carried out.

The geophysical and coincident prospecting targets will be tested by a diamond drill program planned for late January, 2011. The exploration application for the diamond drill program has been submitted to the Newfoundland government and a drill bid request has been sent to five Newfoundland based diamond drilling companies.

The original PH 62 claim property (1,550 ha) is located in the Pope’s Hill area, approximately 100 km from Goose Bay along the paved portion of the TLH. The claims were acquired to cover thorium and REE mineralization located in 2006 during uranium exploration when values of up to 7.9% total rare earth elements plus yttrium (TREE+Y) were located (see news release dated May 6, 2010). Thirty-one samples were taken in follow up exploration in October (see news release dated Oct. 28, 2010). All samples gave anomalous TREE+Y values with 16 > 5%, and 5 > 10% with a high value of 24% TREE+Y. TREE+Y values varied from a low of 0.07% to a high of 24.07% averaging 5.73% for the 31 samples, which included 7 “host rock” samples, with values < 0.2%. The anomalous trend has been traced over a 7 km strike length extending to the east, approximately 4 km, and to the west, approximately 3 km, from a bedrock aggregate pit on the TLH. The highest REE values are in a dark grey to black sub-metallic mineral in veins which are variably non magnetic to moderately magnetic. All of the REE bearing samples are weakly to moderately radioactive with significant thorium content and minor uranium values generally < 100 ppm.

Rock units on the claims are mapped as granitic to mafic gneisses of late Paleoproterozoic age, with some pegmatites. Linear monzonite bodies, possibly related to a major structure, lie just to the north and south, along strike, of the mineralized area. Syenites and/or granitic units of peralkaline affinity have been noted.

Maps showing the property location, a compilation map for the property, the geophysical results and a picture of the bedrock pit can be viewed below:

A total of 1,297 claims (324 km2), extending 40 km northeast and 40 km southwest of the original showings, were acquired by SSE in late October (news release Oct. 28, 2010) to protect the on-strike extensions of the mineralized zone and strongly anomalous lake sediment values in La and Ce with values up to 690 ppm against a background of 30 ppm. The 100% owned property, with the original 62 claim property included, now totals 1,359 claims (approx. 340 km2).

Analyses on the Pope’s Hill rock samples in 2006 were carried out at the ACME Laboratories facility in Vancouver, BC after sample preparation at Eastern Analytical in Springdale, NL. They were analyzed by a REE package (Group 4B REE), which consists of a 0.2 g sample treated by a LiBO2 fusion followed by an ICPMS finish. All 2010 rock analyses are done at the Activation Laboratories (Actlabs) facility in Ancaster, Ontario after sample preparation at their facility in Goose Bay. The analysis is by their Code 8 REE package which uses a lithium borate fusion and then analysis by either ICP or ICP-MS. Values were checked by Actlabs using internal standards.


Gravity and mag for REE in Nebraska

Posted by on Thursday, 16 December, 2010

Quantum Rare Earth Developments Corp.  announces that it has retained the services of Fugro Airborne Surveys Corp. of Ottawa, Ontario for a high-resolution airborne gravity and magnetic survey of the Elk Creek Carbonatite, located in southeast Nebraska.

The Elk Creek Carbonatite is an intrusive complex of carbonatite and related rocks, and is host to significant niobium and rare earth element (REE) mineralization.  The property was held under an option agreement during the 1970’s and 1980’s by Molycorp Inc., at which time considerable exploration of the project took place.  At least 113 core holes were completed within the outline of the seven-kilometre-diameter geophysical anomaly, with 25 holes completed within a core zone, where high-grade niobium mineralization was identified.  Based upon the exploration a historic resource estimate of “39.4 million tons of 0.82 per cent Nb2O5, and is open to the north, west and at depth”, was prepared by Molycorp Inc. for this core zone (Molycorp internal memorandum, Feb. 5, 1986).


In addition to the historic core zone of niobium mineralization, anomalous niobium and REE mineralization was identified during the wide-spaced exploration drilling of the property by Molycorp Inc.  Highlights include:

- Hole EC-40, northeast of the Core Zone, intersected 24.4 metres of 0.65 per cent Nb2O5, and 0.31 per cent rare earth oxides (REO);
- Hole EC-55, within the Western Anomaly, intersected 192 m of 1.31 per cent REO’s, including 33.5 m of 2.09 per cent REO’s; and
- Hole EC-93, within the Eastern Anomaly, intersected 140.2 m of 2.19 per cent REO’s, including 18.3 m of 3.12 per cent REO’s.

The Elk Creek Carbonatite is defined by an oval-shaped magnetic and gravity anomaly approximately 7 kilometres in diameter, making it one of the largest carbonatite complexes known worldwide.  Associated with the carbonatite and carbonatite breccias are lesser amounts of basalt, lamprophyre, and syenite.  These Late Proterozoic-age intrusive rocks are situated approximately 200 metres below an almost flat-lying cover of Pennsylvanian-aged marine carbonate and shale.

It is anticipated that the airborne survey will be initiated within the next few weeks and will take four to five days to complete. The survey represents the first modern geophysical methods applied to the Elk Creek Project since the late 1970’s to early 1980’s, and represent the first step in the exploration of the project by Quantum Rare Earth Developments Corp.  Data from the survey will be used to assist with the planning of the ongoing exploration and development of the project.  A total of 1,160 line kilometers will be completed, with 200-m spaced lines.

All niobium and rare earth element drill results, as well as estimates of historic resources predate, and are therefore non-compliant with, National Instrument 43-101 (NI 43-101) reporting standards. The company is not treating the historical estimates as current mineral resources or reserves. The company has not undertaken any independent investigation of the drill results or resource estimates, nor has it independently analyzed the results of the previous exploration work in order to verify the resources, and therefore the historic drill results and estimates should not be relied upon. The company believes that these historical drill results and estimates provide a conceptual indication of the potential of mineral occurrences within the project, and are relevant to the ongoing exploration.

About Carbonatites:  Carbonatites are very rare and unique rock types, with approximately 500 complexes known worldwide. Often containing a variety of exotic minerals, carbonatites have been known to produce economic concentrations of rare earth elements, niobium, copper, iron, apatite, vermiculite and fluorite; with significant byproducts which may include barite, zircon, tantalum, gold, silver, uranium, nickel and platinum group elements.


Geophysics in Exploration of Rare Earth Elements

Posted by on Sunday, 29 November, 2009

Virginia Heffernan analyses  nature of growing interest in REEs and the role of geophysics in exploration of the mineral deposits.

Economic concentrations of these REE-bearing minerals are generally hosted in, or associated with, alkaline igneous rocks and carbonatites. Airborne magnetic, radiometric, and gravity surveys can be used to delineate the host rocks. Because many carbonatite complexes are surrounded by mafic alkaline rocks, they often show up as a magnetic bull’s eye combined with a gravity low and ringed by a gravity high.

“In general, the host rocks to rare earth deposits are good geophysical responders,” says David Trueman, an expert on REE exploration. “On the ground, geophysics is a secondary tool that might help look for responsive minerals affiliated with the deposit itself.”

Radiometrics, for example, can be an extremely useful technique if the REE deposit is associated with thorium or uranium, as they tend to be. Both Thor Lake and the Mountain Pass carbonatite in California, which has been mined for REEs since 1954, were first discovered during prospecting for uranium.

About recent discovery in Quebec see also http://explorationgeophysics.info/?p=195


Reconnaissance evaluation of magnetic feature led to discovery in Quebec

Posted by on Thursday, 19 November, 2009

Quest Uranium Corporation reports that a new rare earth elements (REEs) discovery has been made on its Misery Lake property, approximately 120 km south of the Corporation’s Strange Lake REE project area. Mineralization is associated with magnetite-rich magmatic segregation layers and zones of iron-enrichment within the peripheral intrusive phase of the Misery Lake intrusive complex. The complex is manifested as a 6-km diameter airborne magnetic anomaly and translates into a target feature that has a potential strike length continuation of approximately 20 km. The airborne geophysics was completed by MPX Geophysics of Concord, Ontario.