Riverstone Resources Inc.

Riverstone Resources Inc.

October 03, 2012 11:47 ET

Riverstone Announces Update of Gold Mineralization at Karma Project

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Oct. 3, 2012) - Riverstone Resources Inc. (TSX VENTURE:RVS)(OTCQX:RVREF)(FRANKFURT:3RV) ("Riverstone" or the "Company") announces an updated independent NI 43-101 compliant Mineral Resource estimate, that shows an increase of 27% for the Indicated in-pit mineral inventory and 23% for the global mineral inventory compared to the January, 2012 resource estimate at its flagship Karma gold project (the "Karma Project") in Burkina Faso, West Africa (See Riverstone's news release dated January 9, 2012). The NI 43-101 compliant resource estimate has been completed by P&E Mining Consultants Inc. ("P&E") of Brampton, ON. The estimate was completed on the Goulagou I, Goulagou II, Kao, Rambo and Nami deposits, which are all in close proximity to each other.

HIGHLIGHTS (resources are contained within five Whittle open pit shells)

  • Global Mineral Inventory (inside and outside of Whittle pit shells) consists of Indicated gold mineralization totalling 2,252,000 ounces of gold in 68.8 Mt at an average grade of 1.02 g/t Au and Inferred gold mineralization totaling 1,115,000 ounces of gold in 40.4 Mt at an average grade of 0.86 g/t Au.
  • A significant portion of the gold resources are at shallow depth (less than 200 metres vertical depth) and over 72% of the global mineral inventory is contained with the five Whittle pit shells.
  • Total Indicated gold resources within five Whittle pits are 1,943,000 ounces of gold in 56.5 Mt at an average grade of 1.07 g/t Au.
  • Total Inferred gold resources within five Whittle pits are 492,000 ounces of gold in 15.4 Mt at an average grade of 1.00 g/t Au.
  • 80% of the resources within the Whittle pit shells are classified as Indicated gold resources.
  • Mineralization remains open at depth and along strike in at least one direction for all deposits.
  • This resource will be used as the basis for proceeding with a definitive Feasibility Study (FS) commencing in Q4, 2012 based on total Indicated resources of leachable material containing 1,030,000 ounces of gold, an increase of 24% compared to the resources used in the August 20, 2012 PEA.

"We are very encouraged with the increase of resources at Karma," commented Dwayne L. Melrose, President and CEO of Riverstone Resources Inc. "This will provide a solid base for going forward with engineering and economic studies in 2012/2013 to establish Karma as one of the premier gold projects in West Africa. There also remains significant potential to continue to increase the gold resource with further drilling in the future."

The Karma Project consists of five separate deposits, which are located in close proximity to each other. A summary of the resource estimates within a Whittle pit shell for each deposit is presented in the table below:

(Within Whittle pit shells)(6)
Deposit Category Cut Off Au g/t Type Tonnes Grade (g/t) Au-oz
GOULAGOU I Indicated 0.20 Oxide 6,651,000 0.62 132,500
0.22 Transition 2,757,000 0.71 62,600
0.50 Sulphide 5,739,000 1.07 197,100
Subtotal 15,147,000 0.81 392,200
Inferred 0.20 Oxide 1,518,000 0.79 38,400
0.22 Transition 561,000 0.81 14,500
0.50 Sulphide 2,762,000 1.04 92,400
Subtotal 4,841,000 0.93 145,300
GOULAGOU II Indicated 0.20 Oxide 6,403,000 1.16 237,900
0.22 Transition 1,835,000 1.44 85,000
0.50 Sulphide 4,744,000 1.67 255,500
Subtotal 12,982,000 1.39 578,400
Inferred 0.20 Oxide 709,000 0.74 17,000
0.22 Transition 339,000 1.05 11,400
0.50 Sulphide 1,432,000 1.35 62,200
Subtotal 2,480,000 1.14 90,600
KAO Indicated 0.20 Oxide 9,552,000 0.87 268,300
0.22 Transition 2,953,000 0.97 92,200
0.50 Sulphide 11,743,000 1.22 459,900
Subtotal 24,248,000 1.05 820,400
Inferred 0.20 Oxide 2,355,000 0.60 45,100
0.22 Transition 345,000 0.73 8,100
0.50 Sulphide 4,654,000 1.22 182,700
Subtotal 7,354,000 1.00 235,900
NAMI Indicated 0.20 Oxide 656,000 0.96 20,200
0.22 Transition 1,063,000 0.72 24,700
0.22 Sulphide 1,561,000 0.82 40,900
Subtotal 3,280,000 0.81 85,800
Inferred 0.20 Oxide 127,000 0.85 3,500
0.22 Transition 167,000 0.79 4,200
0.22 Sulphide 198,000 0.74 4,700
Subtotal 492,000 0.79 12,400
RAMBO Indicated 0.20 Oxide 200,000 2.19 14,100
0.22 Transition 261,000 2.83 23,800
0.22 Sulphide 357,000 2.46 28,300
Subtotal 818,000 2.51 66,200
Inferred 0.20 Oxide 115,000 1.33 4,900
0.22 Transition 51,000 0.53 900
0.22 Sulphide 43,000 1.52 2,100
Subtotal 209,000 1.17 7,900
TOTAL Indicated 0.20 Oxide 23,462,000 0.89 672,900
0.22 Transition 8,869,000 1.01 288,200
0.22 & 0.50 Sulphide 24,145,000 1.26 981,700
Total 56,476,000 1.07 1,942,800
TOTAL Inferred 0.20 Oxide 4,825,000 0.70 108,900
0.22 Transition 1,463,000 0.83 39,200
0.22 & 0.50 Sulphide 9,090,000 1.18 344,100
Total 15,378,000 1.00 492,200
(1) Resource estimates were based on a gold price of US$1,415 per ounce, a 92% to 85%, 90% to 76% respective leach recoveries for oxide and transition and flotation recoveries of 89% to 96% for sulphides; oxide and transition mining costs of US$1.60/tonne and US$1.80 per tonne for sulphide; process costs of US$6.20/tonne for oxide and transition and US$17.00 per tonne for sulphide; and General & Administrative costs of US$1.70 tonne were used to determine the respective 0.20, 0.22 and 0.50 oxide, transition and sulphide open pit cut-off grades.
(2) Au grades were estimated in a 5m x 5m x 5m block model (except Rambo at 2.5m x 2.5m x 2.5m blocks) from capped 2.0m composites utilizing inverse distance cubed interpolation. Composites were capped up to 45 g/t depending on the individual mineralized domain.
(3) Mineral resources which are not mineral reserves do not have demonstrated economic viability.The estimate of mineral resources may be materially affected by environmental, permitting, legal, title, taxation, sociopolitical, marketing, or other relevant issues.
(4) The quantity and grade of reported Inferred resources in this estimation are uncertain in nature and there has been insufficient exploration to define these Inferred resources as an Indicated or Measured mineral resource and it is uncertain if further exploration will result in upgrading them to an Indicated or Measured mineral resource category.
(5) The mineral resources in this press release were estimated using the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM Standing Committee on Reserve Definitions and adopted by CIM Council.
(6) Material within Whittle pit shells have engineering mining aspects derived from the Sep 2012 Preliminary Economic Assessment applied to the global mineral inventory.
(7) Readers are cautioned that at the time of this press release, the exploration permitscovering the Goulagou I, Goulagou II, Rambo and Nami deposits are expired pending the issuance of an exploitation permit over the Goulagou I, Goulagou II and Rambo deposits by the Ministry of Mines for Burkina Faso. There is a reasonable expectation, however no guarantee, that in the near future that these exploitation permits will be issued. The exploration permit for the Kao deposit expires September 2013.

The resource estimation is based on a total of 1,220 diamond and reverse circulation drill holes for 183,374 metres. Subsequent to the January 2012 resource estimation, a total of 383 new diamond and reverse circulation holes for 77,641 metres are credited to the resource update.

Riverstone will continue with the on-going drill program to further extend and upgrade the resource quality of the 5 deposits and also to test regional targets throughout the remainder of 2012 and into 2013.

All reported resources fell within the limits of the mineralized wire frames. All interpolated grade blocks or partial blocks within the resource wire frames need to have at least three composites from two holes within 50 metres to be classified as Indicated Resource. Inferred Resources were determined from the remaining blocks, or partial blocks that lie within the wire frames.

(within and outside of Whittle pit shells)
Deposit Category Cut Off Au g/t Type Tonnes Grade (g/t) Au-oz
GOULAGOU I Indicated 0.20 Oxide 7,131,000 0.61 139,200
0.22 Transition 3,338,000 0.67 71,900
0.50 Sulphide 8,720,000 0.96 269,700
Subtotal 19,189,000 0.78 480,800
Inferred 0.20 Oxide 1,794,000 0.73 42,300
0.22 Transition 1,039,000 0.67 22,400
0.50 Sulphide 7,586,000 0.85 207,200
Subtotal 10,419,000 0.81 271,900
GOULAGOU II Indicated 0.20 Oxide 6,480,000 1.15 239,000
0.22 Transition 1,961,000 1.38 87,000
0.50 Sulphide 5,920,000 1.56 296,600
Subtotal 14,361,000 1.35 622,600
Inferred 0.20 Oxide 805,000 0.70 18,200
0.22 Transition 450,000 0.90 13,000
0.50 Sulphide 4,884,000 1.12 176,400
Subtotal 6,139,000 1.05 207,600
KAO Indicated 0.20 Oxide 10,384,000 0.84 280,600
0.22 Transition 3,303,000 0.93 98,500
0.50 Sulphide 16,298,000 1.14 596,400
Subtotal 29,985,000 1.01 975,500
Inferred 0.20 Oxide 4,768,000 0.49 75,500
0.22 Transition 1,562,000 0.51 25,700
0.50 Sulphide 14,895,000 0.98 468,900
Subtotal 21,225,000 0.84 570,100
NAMI Indicated 0.20 Oxide 668,000 0.95 20,300
0.22 Transition 1,091,000 0.71 25,000
0.22 Sulphide 2,448,000 0.72 56,700
Subtotal 4,207,000 0.75 102,000
Inferred 0.20 Oxide 155,000 0.80 4,000
0.22 Transition 191,000 0.75 4,600
0.22 Sulphide 1,059,000 0.54 18,400
Subtotal 1,405,000 0.60 27,000
RAMBO Indicated 0.20 Oxide 206,000 2.14 14,200
0.22 Transition 283,000 2.66 24,200
0.22 Sulphide 518,000 1.95 32,400
Subtotal 1,007,000 2.19 70,800
Inferred 0.20 Oxide 187,000 1.03 6,200
0.22 Transition 128,000 0.53 2,200
0.22 Sulphide 901,000 1.05 30,500
Subtotal 1,216,000 0.99 38,900
TOTAL Indicated 0.20 Oxide 24,869,000 0.87 693,300
0.22 Transition 9,976,000 0.96 306,700
0.22 & 0.50 Sulphide 33,905,000 1.15 1,251,800
Total 68,750,000 1.02 2,251,800
TOTAL Inferred 0.20 Oxide 7,709,000 0.59 146,200
0.22 Transition 3,369,000 0.63 67,800
0.22 & 0.50 Sulphide 29,325,000 0.96 901,300
Total 40,403,000 0.86 1,115,300

Assay data used as a basis in these resource estimates have been independently verified from original assay lab certificates.

The mineral resource estimates in this press release were prepared by Eugene Puritch, P.Eng., Antoine Yassa, P.Geo., and Yungang Wu, P.Geo of P&E, each an independent qualified person, as defined by National Instrument 43-101 ("NI 43-101").

Mr. Puritch has reviewed and approved the contents of this news release. Paul G. Anderson, MSc. P.Geo., the Company's Vice-President of Exploration, is Riverstone's Qualified Person for the purposes of NI 43-101 and has approved the technical content of this news release.

Riverstone is active in Burkina Faso, West Africa, where it holds a portfolio of four high quality exploration projects covering in excess of 2,000 square kilometres. The Company's flagship project is the Karma Project. The results of a Preliminary Economic Assessment have recently been released (see Company news release dated August 20, 2012 and NI 43-101 Technical Report titled, "Preliminary Economic Assessment Report for the Karma Project, Burkina Faso, West Africa", with an effective date of August 2, 2012, filed on SEDAR (www.sedar.com) September 17, 2012), highlighting the Karma Project to be a robust project.

Riverstone maintains a quality control program involving the use of repeat assays, inserted blanks and the use of certified standards from an accredited Canadian laboratory. All samples were prepared at the independent Abilab Burkina SARL laboratory in Ouagadougou, Burkina Faso, West Africa (part of the ALS Chemex Group), and assayed using standard fire assay with an atomic absorption finish, with samples grading over one gram per tonne gold re-assayed with a gravimetric finish, either in Burkina Faso or at an ALS Chemex facility in North Vancouver, British Columbia, Canada, or in Johannesburg, South Africa.

Addition information about the Company and its activities may be found on the Company's website at www.riverstoneresources.com and under the Company's profile at www.sedar.com.


Dwayne L. Melrose, President & CEO

Certain statements made and information contained in this news release and elsewhere constitutes "forward-looking information" within the meaning of Canadian securities legislation. Such forward-looking statements are based on certain assumptions and are subject to risks and uncertainties which could cause actual events or results to differ from those reflected in the forward-looking statements, including, without limitation, with respect to statements regarding the updated resources estimate, the assumptions set forth in this news release and in the Company's news releases of January 9, 2012, August 20, 2012 and risks and uncertainties relating to the interpretation of drill results and the estimation of mineral resources, the geology, grade and continuity of mineral deposits, the possibility that future exploration, development results will not be consistent with the Company's expectations, accidents, equipment breakdowns, risk of undiscovered, title defects and surface access, labour disputes, the potential for delays in exploration and permitting activities, the potential for unexpected costs and expenses, commodity price fluctuations, currency fluctuations, political risk and other risks and uncertainties, including those described under Risk Factors in each management discussion and analysis and in the Company's annual information form which are available under the Company's profile at www.sedar.com. Forward-looking information is based on various assumptions including, without limitation, the expectations and beliefs of management, the assumed long term price of gold, that the Company will receive required permits and access to surface rights, that the Company can access financing, appropriate equipment and sufficient labour and that the political environment within Burkina Faso will continue to support the development of environmentally safe mining projects. Should one or more of these risks and uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described in forward-looking statements. Accordingly, readers are advised not to place undue reliance on forward-looking statements.

This news release may use the terms "measured", "indicated" and "inferred" as these terms are defined under Canada's National Instrument 43.101. U.S. Investors are advised that, while such terms are recognized and required by Canadian regulations, they are not recognized by the United States Securities and Exchange Commission ("SEC") and may not be comparable to similar information for United States mining or exploration companies. As such, certain information contained on this news release concerning descriptions of mineralization and resources under Canadian standards is not comparable to similar information made public by United States companies subject to the reporting and disclosure requirements of the SEC. U.S. investors are cautioned not to assume that any part or all of the mineral deposits described in these categories will ever be converted into proven or probable reserves, as defined in the SEC's Industry Guide No. 7.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Contact Information

  • Riverstone Resources Inc. - Vancouver Office
    Dwayne L. Melrose

    Riverstone Resources Inc.
    Don Mosher
    Corporate Development

    Riverstone Resources Inc.
    Raju Wani
    Investor Relations

    Riverstone Resources Inc.
    Ron Cooper
    Investor Relations