Montero Mining and Exploration Ltd

Montero Mining and Exploration Ltd

September 08, 2011 10:09 ET

Montero Identifies a Massive New Zone With Bastnaesite Over 256m at 0.6% TREO at the Tumbili Target at the Wigu Hill Rare Earth Project, Tanzania

TORONTO, ONTARIO--(Marketwire - Sept. 8, 2011) - Montero Mining and Exploration Ltd. (TSX VENTURE:MON) ("Montero") is pleased to announce the completion of a 1,525m drilling program at the Tumbili target on the south east side of the Wigu Hill carbonatite complex and the discovery of a broader zone of mineralized carbonatite breccia, some with consistent distribution of rare earth mineralization at the Wigu Hill REE Project in Tanzania.

The drilling in association with surface mapping and trenching has established that the Tumbili target is an extensive zone of massive intrusive carbonatite breccias and associated dolomitic carbonatite that are interpreted to form the central core of the high-grade intrusive carbonatites at Wigu Hill. In addition, significant TREO values have previously been returned from individual samples of material from within the breccias. The better values from reconnaissance sampling were returned from bastnaesite-rich dikes on the upper limits of the breccia zone and from dolomitic carbonatite that exhibits distinctive stockwork textures of bastnaesite-rich veinlets. Significant values were also returned from sampling of the breccia itself in the first trenches on the lower slopes of the Tumbili target where breccia fragments are well mineralized with bastnaesite (see news release dated 07/07/11:

Dr Tony Harwood, President and Chief Executive Officer of Montero commented, "We are delighted with the results of this drilling which confirms the presence of a wide zone of lower grade rare earth bearing bastnaesite mineralization. This is considered to form a part of the core carbonatite intrusive in the central and eastern part of the Wigu Hill complex, where it is associated with the higher grade carbonatite mineralization at Twiga, Tembo and the newly discovered Nyati targets. Continuous mineralization in drill holes of 253m at 0.6% TREO and 200m at 0.7% TREO which remain open at depth, indicate the potential for a sizeable REE mineralized system at Wigu Hill."

The Tumbili Target is located to the east of the centre of the Wigu Hill complex and to the west of the Tembo Target (see news release dated 15/06/11: The continuity of the easterly trending carbonatite breccia zones and associated carbonatite dikes has been confirmed by mapping, trenching and the drilling of 6 core boreholes (1,525m). Of these, the deepest, TUM004 at 334m drilled mainly carbonatite breccias, but with numerous dolomitic carbonatite dikes and fragments. The shallowest, TUM003 at 165m, drilled mainly carbonatite breccias and was stopped when it intersected intensely carbonated gneisses.

The Tumbili Target can be subdivided for reporting purposes into a lower and an upper zone.

The Lower Tumbili zone is made up almost entirely of buff coloured carbonatite breccias. The matrix is fine to medium grained and tuffaceous, while the fragments vary in size from a few millimeters to greater than a metre, in places well mineralized with bastnaesite. Mineralization in the breccia from trench TUM001 assayed at 2.97% TREO over 12.00m

Assay results from the three boreholes, TUM001, 002 and 003 drilled on Lower Tumbili returned some positive results but with lower grades than anticipated, however, the massive zone identified shows potential for bulk tonnage. The best intersection in BH TUM001 is 1.04% TREO over an apparent width of 80.40m (Fig 1). As the dip of the massive zone is generally into the hill to the north, this width is close to a true width. The mineralization in BH TUM002 is also encouraging with a continuous zone grading at 1.00% TREO over 37.0m apparent width. The width of mineralization diminishes to the east within the breccia zone, where a zone grading at 1.13% TREO over a width of 5.10m was intersected. (For details refer to Table 1 below).

To view a section of BH TUM001 on Lower Tumbili (Fig. 1):

Borehole number From To Geology Apparent
Width in m
Grade of
BH TUM0001 0.00 4.00 Cbr 4.00 1.56
4.00 96.00 Cbr 92.00 0.34
96.00 106.00 Cbr 10.00 1.10
106.00 120.00 Cbr 14.00 0.61
120.00 200.40 Cbr 80.40 1.04
Total 0.00 200.40 Cbr 200.40 0.702
BH TUM002 0.00 8.00 Cbr 8.00 1.29
8.00 61.50 Cbr 53.50 0.40
61.50 62.60 Cbr 1.10 2.73
62.60 89.00 Cbr 26.40 0.57
89.00 104.00 Cbr 15.00 0.98
104.00 111.00 Cbr 7.00 0.47
111.00 114.00 Cbr 3.00 2.61
114.00 124.00 Cbr 10.00 0.45
124.00 128.00 Cbr 4.00 2.20
128.00 178.00 Cbr 50.00 0.47
178.00 215.00 Cbr 37.00 0.99
215.00 253.80 Cbr 38.80 0.36
Total 0.00 253.80 Cbr 253.80 0.61
BH TUM003 0.00 8.00 Cbr 8.00 0.16
8.00 139.00 Cbr 131.00 0.27
139.00 144.10 Cbr 5.10 1.13
144.10 165.20 Gnc 21.10 0.31
Total 0.00 165.20 Cbr/Gnc 165.20 0.31
Cba Bastnaesite-rich Carbonatite
Cca Dolomitic carbonatite
Cfe Ferruginous carbonatite
Cbr Carbonatite breccia with tuffaceous matrix
Gnc Carbonate altered gneisses
Table 1. TREO graded assay data from BHs TUM001, TUM002 & TUM003 at Lower Tumbili.

The Upper Tumbili zone is dominated by carbonatite breccias, which also have a matrix that is fine to medium grained and tuffaceous. Generally, the breccia fragments small, but variable in size. Three boreholes have been drilled to date on this zone ranging in depth from west to east as follows, BH TUM005, 298.30m, BH TUM004, 334.10m and BH TUM 006, 273.30m. Numerous narrow bands of dolomitic carbonatite were intersected within these boreholes. Assay results from the samples submitted have not yet been received.

Trenching at Upper Tumbili in association with surface geological mapping has been instrumental in gaining a better understanding of the geology. Broad zones of massive dolomitic carbonatite can be traced along strike for significant distances of 150m to 200m. The mineralization observed in Trenches TUM1A and TUM2 and the assay results returned in particular have been very positive. The results from these two trenches are summarized below:-

Trench No From To Geology Apparent
Width in m
Grade of
Maximum Value
TUM1A 0.00 7.40 Cbr 7.40 0.31
7.40 33.10 Cbr 25.70 1.55 3.67% over 0.96m
33.10 44.30 Cbr 11.20 0.60
44.30 62.30 Cba 18.00 3.02 9.44% over 2.30m
84.10 115.08 Cbr 30.98 0.40
TUM2 0.00 29.60 Cbr 29.60 0.55
29.60 67.00 Cbr 37.40 2.03 6.01% over 2.00m
67.00 85.00 Cbr 18.00 1.00 1.94% over 2.00m
Table 2. TREO values from Trenches TUM1A and TUM2.

Within trench TUM 1A, the best REE mineralization occurs within an 18m wide section which returned values of up to 9.44% TREO over an apparent width of 2.30m. Here bastnaesite bearing crystals are clearly visible. The mineralized dikes exposed in these trenches can be traced northwards into a broader and more massive zone of mineralized dolomitic carbonatite, which has been called the Nyati Target (Fig 2). This zone is traversed by major sets of well mineralized veins and veinlets with abundant bastnaesite and in places also some monazite.

To view a photographic image showing the location of the Nyati Target relative to the Tumbili Target (Fig. 2):

The Nyati Target

The Nyati Target has been identified to the north of upper Tumbili Target, this has been traced to date over an area of 800m along strike, 400m in width and is open ended in width and along strike. Reconnaissance mapping of this new zone has been completed, and 100 well mineralized carbonatite samples taken and submitted for analysis. To date some very positive results have been returned for the bastnaesite-rich veins in carbonatite breccias from the Tumbili Target. Geological mapping has located an extensive carbonatite stockwork zone north of the Upper Tumbili zone, which appears to host greatly improved rare earth mineralization.

This Nyati Target will be the focus of the next stage of exploration and core drilling at Wigu Hill.

Discussion on the analytical procedures:

Certified Standard: A certified standard was prepared by AMIS (African Mineral Standards) in Johannesburg, South Africa. This standard was used as reference material in the analysis of the samples reported here.

Analytical Laboratory: The samples presented here were analysed by ALS Chemex in Vancouver after sample preparation was undertaken at their facility in Mwanza, Tanzania. The AMIS certified standard was inserted as sealed packets at intervals of 20 samples. Analyses for REE elements are performed by lithium meta-borate fusion and ICP-MS, an analytical package of 38 elements. Rock forming elements are analysed by lithium meta-borate fusion followed by dissolution of the melt and ICP-AES analysis. An option is available to analyse over limit REE's by ME-OGREE. For this batch of assays no samples were analysed for Ce, La and Pr to quantify the higher values of these elements.

Definition of TREO: The use of the term TREO (Total Rare Earth Oxides) in this release includes only the 15 defined rare earth oxides, namely:- Most abundant – CeΓééOΓéâ, LaΓééOΓéâ, NdΓééOΓéâ, PrΓééOΓéâ and SmΓééOΓéâ (referred to as light rare earth oxides). These 5 Rare Earth Oxides make up over 99% of the rare earth element content, particularly for values >1% TREO. Others:- EuΓééOΓéâ, ErOΓéâ, DyΓééOΓéâ, GdΓééOΓéâ, HoΓééOΓéâ, HfOΓéé, TbΓééOΓéâ, TmΓééOΓéâ, LuΓééOΓéâ and YbΓééOΓéâ (Pm was not assayed) are present in minor to trace amounts only. Values for elements such as Y or Nb, are not included and have not been reported here.

QA/QC: Montero has used blanks, field duplicates and one analytical standard to monitor the sampling and analytical quality. Results to date for the blank and field duplicates show acceptable quality for the main REEs of interest. The standard used was prepared on behalf of Montero using material from Wigu Hill and has certified analytical values for Ce, La, Pr and Sm based on analyses from 16 different laboratories. A review of the results reported by ALS Chemex, indicates that these meet the required level of analytical quality.

Qualified Person's Statement

The technical information contained in this press release has been reviewed by Mr. Mike Evans, M.Sc. Pr.Sci.Nat., who is a qualified person for the purpose of National Instrument 43-101 and a consulting geologist to Montero. Grab samples are selective by nature and are unlikely to represent average grades on the property.

About Montero Mining & Exploration

Montero Mining and Exploration Limited is a mineral exploration and development company focused on the development of our flagship Wigu Hill Rare Earth Element Project in Tanzania. The Wigu Hill project is a high grade undeveloped Light Rare Earth Element deposit where the company's current focus is on reporting an initial NI 43-101 compliant resource on the first two of ten drill target areas tested to date.

Rare Earth Elements (a group of 15 metals) are critical in the advancement and development of emerging "green" technologies and high-tech applications such as electric and hybrid vehicles, wind and hydro power turbines, energy efficient lighting, LCD screens, MRI, X-ray machines and neodymium-based magnets crucial to ear-buds, MP3 Players, microphones, mobile devices and other computing equipment. Currently China produces 97% of world supply of REE's and these are becoming increasingly critical to both 21stCentury technological progress and environmentally sustainable development. With the rising prices of REE's and China's control over export quotas, it is becoming imperative that the rest of the world develops new rare earth resources to meet the increasing demand from "green" technology.

Montero's growth strategy is to develop the Wigu Hill Rare Earth Element project and to bring this to account through eventual rare earth production and cash flow. Montero plans to operate in an environmentally and socially responsible manner, adding value to all stakeholders. Montero has 52.1M shares outstanding and trades on the TSX Venture Exchange under the symbol MON.

Signed. Dr. Tony Harwood - President and CEO


This News Release includes certain "forward-looking statements". These statements are based on information currently available to the Company and the Company provides no assurance that actual results will meet management's expectations. Forward-looking statements include estimates and statements that describe the Company's future plans, objectives or goals, including words to the effect that the Company or management expects a stated condition or result to occur. Forward-looking statements may be identified by such terms as "believes", "anticipates", "expects", "estimates", "may", "could", "would", "will", or "plan". Since forward-looking statements are based on assumptions and address future events and conditions, by their very nature they involve inherent risks and uncertainties. Actual results relating to, among other things, results of exploration, project development, reclamation and capital costs of the Company's mineral properties, and the Company's financial condition and prospects, could differ materially from those currently anticipated in such statements for many reasons such as: changes in general economic conditions and conditions in the financial markets; changes in demand and prices for minerals; litigation, legislative, environmental and other judicial, regulatory, political and competitive developments; technological and operational difficulties encountered in connection with the activities of the Company; and other matters discussed in this news release. This list is not exhaustive of the factors that may affect any of the Company's forward-looking statements. These and other factors should be considered carefully and readers should not place undue reliance on the Company's forward-looking statements. The Company does not undertake to update any forward-looking statement that may be made from time to time by the Company or on its behalf, except in accordance with applicable securities laws.

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