Oromin Explorations drills six m of 81.83 g/t at OJVG
Ticker Symbol: C:OLE

Oromin Explorations drills six m of 81.83 g/t at OJVG

Oromin Explorations Ltd (2) (C:OLE)
Shares Issued 135,572,829
Last Close 5/11/2011 $1.10
Thursday May 12 2011 – News Release

Mr. Chet Idziszek reports

OJVG ANNOUNCES RESOURCE UPDATE, NEW DRILL RESULTS AND ADDITIONAL MINERAL POTENTIAL

Oromin Explorations Ltd., (“Oromin”), on behalf of Oromin Joint Venture Group Ltd., (“OJVG”) is pleased to announce the results of mineral resource updates completed by SRK Consulting (Canada) Inc. (“SRK”) for the OJVG Gold Project in Sénégal, West Africa. Oromin is also pleased to report estimates of additional mineral potential that exist downdip of the current resource models that are not included in this resource update. In addition, we continue to discover new deposits and new zones within existing deposits, details of which are reported below.

Chet Idziszek, Oromin’s President and CEO, stated, “the resource update announced today and the heap leach PEA announced last week highlight the ongoing growth in scale and attractiveness of the OJVG Gold Project and we continue to believe that this year will see further success through exploration and engineering activities. Most significantly, we are very pleased to have confirmed the continuity of mineralization beneath the Masato 2010 reserve pit and have delineated almost three quarters of a million ounces of indicated gold resources that we believe is amenable to underground mining. Additionally, we are working jointly with our equal partner, Bendon International, to examine development, financing and strategic alternatives to maximize value from our collective 87% interest in what we both see as one of West Africa’s next gold mines.”

Golouma Style Deposit Resources

In addition to providing a basis for an updated geological and mineral zone interpretation at the Golouma style deposits, drilling in the latter half of 2010 was intended to expand the mineral resources at depth to an indicated level of classification so that the process of identifying new mineral resources and subsequent conversion to mineral reserves can be expedited. This involved not only drilling the down dip extensions of the deposits, but drilling them at tight enough spacing so resources could be largely classified as indicated. As a result of this close spaced drilling, OJVG has confirmed excellent continuity at depth, giving even greater confidence in the down dip potential of the Golouma West, Golouma South, and Kerekounda deposits. In addition, the close proximity and overlapping infrastructure design for two of these similar style deposits from the 2010 Feasibility Study suggests that Golouma West and Golouma South should now be considered as one deposit and will be reported as such henceforth.

This Resource estimate update involved a complete re-interpretation by SRK of the geologic and mineralized models of all Golouma Style deposits. As a result of the remodelling, the following improvements have been made:

– Overall increase in indicated and inferred resources;
– Geological interpretation has improved confidence and increased continuity of mineralisation within the deposits and their downdip projections
– Average depth extent of resource definition increased from 250 metres to 350 metres from surface – Volume of Golouma Style deposits’ wireframes has increased by 24%
– Wireframes for all deposits have been redesigned for a lower cut off grade and successfully demonstrate the greater tonnage potential, large scale continuity and a resource model more conducive to underground mining methods. As expected, the new wireframes include lower grade samples which reduce the overall average grade.
A total of 78 drill holes (29,000 metres) have been completed at Golouma, Kerekounda and Kourouloulou since the previous SRK resource estimates announced in July of 2010 (see news release of July 15, 2010). Compared to the SRK July 2010 resource estimate (constrained by optimized pit), the new drilling (also constrained by optimized pit), revised interpretation and updated resource estimate resulted in a 13% increase (157,000 ounces) in indicated resource ounces and a 24% increase (35,500 ounces) in inferred resource ounces, with the average depth extent of resources increasing from 250 metres to 350 metres from surface.

The Tables below summarizes SRK’s 2011 and previous 2010 combined open pit constrained and underground resources for the Golouma Style Deposits.

May 2011 Combined Open Pit Constrained (cut off grade 0.37 g/t Au) and Underground (cut-off grade 1.0 g/t Au) resources
GOLOUMA STYLE INDICATED RESOURCES INFERRED RESOURCE
Tonnage Grade ContaineTonnage Grade Containe
DEPOSIT Kt g/t Au oz Kt g/t Au oz
Golouma West & So 11,106 2.941,049,40 946 2.78 84,500
Kerekounda 1,470 5.77 272,700 334 5.29 56,700
Kourouloulou 172 9.7 53,800 124 10.85 43,300
TOTAL 12,748 3.361,375,90 1,404 4.09 184,500

July 2010 Combined Open Pit Constrained (cut off grade 0.40g/t Au ) and Underground (cut-off grade 1.0 g/t Au) resources
GOLOUMA STYLE INDICATED RESOURCES INFERRED RESOURCE
Tonnage Grade ContaineTonnage Grade Containe
DEPOSIT Kt g/t Au oz Kt g/t Au oz
Golouma West & S 9,374 3.21 967,000 750 3.28 79,100
Kerekounda 1,073 6.34 218,500 189 3.99 24,300
Kourouloulou 85 11.92 32,500 177 8 45,500
TOTAL 10,532 3.521,218,00 1,116 4.82 148,900

Masato Deposit Resources

The goal for the drill program at the Masato Deposit during the latter half of 2010 was to fully define by infill drilling the deeper, higher grade body of mineralization that extends beneath the proposed pit at the Masato Deposit. Contained within the 2010 and current resource estimate for Masato, the 2010 Feasibility Study defined only open pit probable reserves of 460,000 ounces of gold (10.2 M tonnes at 1.41 g/t Au) as there was insufficient drilling density at that time to delineate a higher grade zone of mineralization beneath the proposed open pit. New drilling at the Masato Deposit consisted of infill drilling that both confirmed continuity and expanded the limits of the deeper, higher grade mineralization. The infill drill spacing was tight enough so that the majority of the deep resource expansion at Masato could be categorized as indicated resources. As a result, OJVG has successfully outlined 721,460 ounces of indicated gold resources below 2010 Feasibility Study open pit at a grade of 2.1 g/t gold.

This resource estimate on the Masato Deposit also involved a complete re-interpretation of the 2010 geologic and mineralized models resulting in an improved geological model, improved continuity and increased the OJVG’s confidence in the down dip potential of the high grade zones of mineralization at depth.

The previous resource estimate for the Masato Deposit was completed by DRA America Inc. and utilized an overall cut off grade of 0.40 g/t Au (but unconstrained by an optimized pit), as opposed to SRK’s methodology of using an optimized Whittle pit shell to constrain their estimate for the purpose of reporting mineral resources that have “reasonable prospects” for economic extraction by an open pit. For the current Masato resource estimate, SRK used an optimized pit shell based on a $1300/oz gold price cut-off and a 1.5 metre minimum thickness to report contiguous mineralization below this pit shell that is potentially amenable to underground mining methods. Although the additional 2010 drilling (completed after the previous DRA resource estimate at Masato) has expanded the down dip extent of the Masato Deposit, the Whittle resource shell used by SRK to constrain the mineral resource resulted in a lower tonnage and contained ounces than reported by DRA in its2010 resource estimate announced in July of 2010.However, the SRK 2011 constrained indicated mineral resource estimate for Masato represents an increase of 139,000 ounces over the SRK 2010 constrained indicated mineral resource estimate, which we believe is a more accurate comparison.

The tables below summarize SRK’s 2010 and 2011 combined open pit and underground resources for the Masato Deposit.

May 2011 Combined Open Pit Constrained (cut off grade 0.37 g/t Au ) and Underground (cut-off grade 1.0 g/t Au) resources for the Masato Deposit

MASATO DEPOSIT 2011 COMBINE INDICATED RESOURCE INFERRED RESOURCE
Tonnage Grade ContaineTonnage Grade Containe
Kt g/t Au oz Kt g/t Au oz
35,531 1.28 1,457,30 3,233 1.25 129,700

July 2010 Combined Open Pit Constrained (cut off grade 0.40 g/t Au ) and Underground (cut-off grade 1.0 g/t Au) resources for the Masato Deposit

MASATO DEPOSIT 2010 COMBINEINDICATED RESOURCE INFERRED RESOURCE
Tonnage Grade ContaineTonnage Grade Containe
Kt g/t Au oz Kt g/t Au oz
35,062 1.17 1,318,70 2,389 1.21 93,300

Since the previous mineral resource estimate at Masato, a total of 14,000 metres in 50 (predominantly infill) drill holes have been completed at Masato. These holes have confirmed the existence and continuity of higher grade mineralisation below the 2010 Feasibility Study open pit which could be amenable to underground mining and which was not included in 2010 Feasibility Study. The table below summarizes the portion of the new resource estimate >1.0 g/t gold cut-off grade that extends below the 2010 reserve pit and will be evaluated as a potential source of underground reserves.

MASATO DEPOSIT INDICATED RESOURCE INFERRED RESOURCE
UNDERGROUND
RESOURCES Tonnage Grade ContaineTonnage Grade Containe
Kt g/t Au oz Kt g/t Au oz
>1.0 g/t Au cut off 10,667 2.1 721,458 1,580 1.99 100,875

All resource modeling was completed by David Rowe, CPG, and Fred Brown, CPG, under the supervision of Wayne Barnett, Pr.Sci.Nat. and Marek Nowak, P.Eng. Quality control checks were undertaken on the sampling and analytical procedures, and on the assay results. All of the resources were modeled using an approximate 0.30 g/t Au grade shell solid for each mineralized zone, except Kerekounda and Kourouloulou which were created with a 1 g/t gold grade shell. Variogram models were created for all of the grade shell solids. Assay data from each grade shell was evaluated and appropriately capped for the purposes of this estimation. Block models were created for each of the grade shells and subsequently constrained at depth and laterally by an optimized Whittle shell based on the following parameters; USD$1,300/oz Au, combined ore mining and processing costs of USD$12.75/tonne, overall pit slope of 45 degrees, metallurgical recovery of 95% and appropriate dilution, offsite costs and royalties.

The reader is cautioned that SRK utilizes results from the conceptual pit optimization work solely for the purpose of reporting mineral resources that have “reasonable prospects” for economic extraction by an open pit and do not represent mineral reserves. Indicated and inferred resource tonnage, gold grade and gold content within the optimized pit shell were reported at a 0.37 g/t gold cut off grade. Resource tonnage, gold grade and gold content tabulated from contiguous portions of the mineralization outside of the optimized pit shell, and potentially amenable to underground mining methods, were reported at a 1.0 g/t Au cut off grade.

In the opinion of SRK, the block model resource estimates reported by SRK herein are a reasonable representation of the gold mineral resources found in the Golouma West, Golouma South, Kerekounda, Kourouloulou and Masato deposits at the current level of sampling. Mineral resources for these deposits are reported in accordance with the guidelines of the Canadian Securities Administrators National Instrument 43-101, and have been estimated in conformity with generally accepted CIM “Estimation and Mineral Resource and Mineral Reserve Best Practices” guidelines. Mineral resources are not mineral reserves and do not have demonstrated economic viability. The resource estimate was completed by Wayne Barnett, Pr.Sci.Nat.(#400237/04), an independent qualified person as this term is defined in National Instrument 43-101.

Additional Mineral Potential (Golouma, Masato and Kerekounda only)

As demonstrated by the recent deep drilling results, significant upside potential exists within and surrounding many of the OJVG gold deposits as many of the deposits remain open to depth and in some cases along strike. OJVG’s recent focus has been to expand the resources down dip of the known deposits by conducting wide spaced, deep drilling in order to delineate the down dip extensions of mineralization extending from the known deposits. OJVG will continue this program of wide spaced step out drilling concurrent with follow up drilling at a number of the recent discoveries. Since January 2011, the OJVG has made three new gold discoveries (Saboraya, Kourouloulou South, 950 Zone) in addition to their nine deposits and two previously identified gold targets at Kinemba and Koutouniokolla.

At the OJVG’s three largest deposits, the current 0.3 g/t gold grade shell solids extend to an average depth of only 350 metres below surface. To date, the Golouma (Golouma West and Golouma South), Kerekounda and Masato deposits have now been successfully intersected at depths of 900 metres, 560 metres, 490 metres and 565 metres respectively, and all remain open to depth. (See attached representation of the Golouma Deposit-South deep drilling results to date). Although insufficient drilling has been conducted to allow classification of this mineral potential as a resource, the OJVG has targeted these contiguous extensions to the known deposits with their current drill program and estimated the potential quantity of gold mineralization beneath the current resource estimates. These deeper potential zones of mineralization have been defined by extending the known dimensions of the 1.0 g/t gold resource grade shell solids down dip to a minimum of 675 metres and a maximum of 1000 metres below surface. It should be recognized that the zones listed have been intersected by multiple drill holes, are areas where current knowledge of mineralization is sufficient to indicate that these zones are economically viable, and only represent the down dip potential of the listed deposits. The table below lists the potential of each of these zones. There are numerous additional targets within the OJVG Gold Project, including the recent discoveries, that are not included in the list below.

Additional Mineral Potential at Golouma, Kerekounda and Ma
Deposit Tonnage Range Grade Range Au (g/t)

Golouma 12,000 to 24,03 to 5
Kerekoun2,000 to 3,5005 to 6
Masato 10,000 to 20,01 to 1.5

The approximate tonnages and grades listed have been derived by the following procedure; the volume of each potential mineral deposit has been derived by extending the known 0.3 g/t gold, three-dimensional grade shells for the Golouma West, Golouma South, Kerekounda and Masato deposits directly down dip to a 1,000-metre depth and calculating the volume of each new solid down to depths of both 675 metres (representing the minimum target tonnage) and 1,000 metres (representing the maximum target tonnage) below surface.

the range in tonnage of the mineralized material to the 675 metre and 1000 metre depths was calculated by multiplying the volume of each new solid by the mean average density (Specific Gravity = 2.82) of the unoxidized ore bodies immediately up dip. The resulting tonnage for each new solid was reduced by a factor to account for the higher gold grade core amenable to underground mining. This factor was determined from the ratio of tonnage of the >1.0 g/t gold to >0.3 g/t gold blocks in the corresponding resource block models immediately up dip of the new solid.

grade ranges have been derived by using the average inferred resource grade for each corresponding up dip resource as a minimum grade and the average open pit reserve grade contained within the corresponding reserve block immediately up dip of the new solids as the maximum grade.

These tonnages or grade ranges should not be construed as true minimums or maximums, only a reasonable means to establish the range of estimates of potential tonnages and grades for future drill targets.

The resulting potential ranges of quantities and grades listed above are conceptual in nature having been based on geologic knowledge, interpretation and wire-framing. There has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in any of the targeted areas being delineated as a mineral resource. OJVG currently plans to focus on further exploration drilling within these potential mineral deposits during 2011 and beyond.

Exploration Drilling Update

OJVG has completed a number of drill holes designed to test the down dip potential beneath the resource shells at the Golouma, Kerekounda and Masato deposits. Both recentand previous announced drill results from this deep drilling exploration program confirm that gold mineralization extends well below the current resource shells at all of these deposits. Highlights are listed below with more detailed results provided in the attached appendix:

Drill From – To IntervalGold Grade
Hole (m) (m) (g/t)
DH-969 569-575 6 81.83
incl.573-574 1 481
DH-970 589-595 6 32.05
incl.590-592 2 87.32
incl.590-591 1 146.8
DH-971 631-642 11 4.81
DH-956 489-491 2 10.3
DH-967 335-348 13 2.4
incl.335-340 5 3.99

While carrying out OJVG’s deep drilling program targeting mineralization below the current resource shells, a new zone was intersected with the westernmost hole (DH-971) at Golouma. This new, apparently sub-parallel zone, referred to as the Golouma West Extension, returned values of 421.4 g/t gold over a three metre interval from 294 to 297 metres in hole DH-971.

Recent drilling has also focused on lateral and depth expansion at the Kinemba discovery, a Masato-style bulk tonnage deposit that is potentially amenable to heap leach processing. To date, wide-spaced drilling has extended the mineralization over a minimum strike length of 550 metres to an average depth of 120 metres and the mineralization remains open. Recent results include 2.16 g/t gold over 14 metres in hole RC-868 and 1.41 g/t gold over 14 metres in hole RC-871. Details for these holes along with three previously reported holes are set out in the attached appendix.

Building Value

Since the 2010 Feasibility Study, there have been two major enhancements to the project’s NPV. In July 2010, the OJVG Feasibility Study defined a NPV of $361 million using $1,200/ounce gold and a 3% discount rate. Since that study, the OJVG has completed optimization studies on the plant design and more recently the heap leach potential of four deposits and waste material not included in the 2010 Feasibility Study economics. The table below summarizes the additive impact these enhancements have on the overall project value.

Average Annual Life of Mine Production
Average Annual Product (9 years)
1st 3 years NPV @ 3% Pre-Tax
$1,200 gold IRR

2010 Feasibilit 174,000 oz Au 144,000 oz Au $361 M 36%

2010 Optimization Study
7,000 oz Au 7,000 oz Au $40 M N/A

2011 Heap Leach PEA Study
36,000 oz Au 26,300 oz Au $60 M 28%

In addition to the foregoing the following all represent examples of potential to build additional value:

The increase of indicated ounces of gold at the Golouma Style Deposits by 157,000 ounces or 13%;
The identification of additional mineral potential at depth at both the Golouma Style Deposits and the Masato deposits;
The identification of 10.6M tonnes grading 2.1g/t gold of indicated resource at Masato below 2010 reserve pit representing new underground mining target;
Continuing high-grade results at Golouma including:81.83 g/t gold over six metres, 32.05 g/t gold over six metres and 421.4 g/t gold over three metres;
The identification of multiple veins (for example in holes DH-966, DH-969 and DH-971) provides an opportunity for significant flexibility to optimize the mine plan;
Heap Leach potential of the GoloumaStyle deposits remains to be evaluated; Expansion of the Kinemba deposit over a minimum strike length of 550 metres to an average depth of 120 metres and remains open; The Heap Leach potential of all Masato Style Deposits remains open to expansion.
Qualified Persons

A NI 43-101 compliant Technical Report describing the resource updates and PEA findings will be filed on the Company’s website and on SEDAR within 45 days. Doug Turnbull, P. Geo., is a qualified person for the purposes of National Instrument 43-101, and has reviewed and verified the exploration data disclosed in this news release. William Bond, P. Geo., is also a qualified person for the purposes of National Instrument 43-101, and has supervised geologic field procedures. TSL Laboratories in Saskatoon carried out all assaying under industry-standard QA/QC procedures.

Heap Leach Drilling
Drill From – To Interval Gold Grade
Hole (m) (m) (g/t)
RC-868 101-115 14 2.16
incl.108-114 6 3.26
RC-870 89-102 13 1.32
Incl.93-101 8 1.98
Incl.94-96 2 3.95
RC-871 18-Sep 9 0.51
86-91 5 1.61
100-114 14 1.41
Incl.107-113 6 2.69
RC-876 0-8 8 1.32
Incl.0-5 5 1.87
RC-877 99-111 12 0.99
Incl.99-105 6 1.22
RC-878 31-34 3 1.76
39-41 2 1.36
72-81 9 0.8
Incl.73-75 2 1.98
102-111 9 0.96
Incl.102-104 2 1.91
DH-795* 46-51 5 1.92
DH-803* 35-41 6 1.07
141-151 10 2.4
DH-810* 16-21 5 1.73
42-49 7 1.64

*Previously reported.
Mineralized intervals are based on 1-metre samples
utilizing 0.2 g/t gold cut-off levels with a
maximum internal dilution of 2 metres. The
attitude of mineralized intervals varies and
reported mineralized intersections may not represent
true widths.

UNDERGROUND DRILLING

Drill From – To Interval Gold Grade
Hole (m) (m) (g/t)
DH-961 430-437 7 4.2
incl.430-432 2 8.59
DH-966 397-400 3 7.18
423-433 10 5.3
incl.423-425 2 13.21
and 428-430 2 9.5
DH-969 488-492 4 7.37
incl.490-491 1 24.28
569-575 6 81.83
incl.573-574 1 481
DH-970 589-595 6 32.05
incl.590-592 2 87.32
incl.590-591 1 146.8
DH-971 294-297 3 421.4
434-438 4 3.42
631-642 11 4.81
incl.633-640 7 6.03
DH-950* 576-578 2 46.75
716-721 5 1.51

DH-964 387-393 6 2.52
401-405 4 2.66
428-433 5 2.77
DH-967 335-348 13 2.4
incl.335-340 5 3.99

DH-956* 489-491 2 10.3

*Previously reported.
Mineralized intervals are based on 1-metre samples

We seek Safe Harbor.

May 12th, 2011
Categories: Uncategorized . Author: caliche