Mar 28 2013
Clifton Star Resources Inc. ("Clifton Star" or "the Corporation") is pleased to report that it has received the results of a laboratory study conducted by SGS Minerals that succeeded in producing high grade gold concentrates from mineral samples of the Duparquet Project.
Six samples from the Duparquet Project were treated using a cleaner flotation scheme developed by SGS Minerals to recover a high grade gold concentrate. The tests were performed as "locked cycle" tests to simulate full scale plant operating conditions. Cleaner flotation tests were conducted to investigate the recovery of gold in a sulphide concentrate for the purpose of toll smelting as an alternative to the operation of a pressure autoclave (POX), which is part of the mill process flowsheet used in the recently published preliminary economic assessment study ("PEA") on the Duparquet Project (press release dated January 15, 2013).
- The gold grade of the cleaner concentrates ranged from 39 g/t Au to 84 g/t Au and the sulphur grade ranged from 21% S to 36 % S. These grades of gold and sulphur are amenable to toll smelting through copper smelting operations.
- The average overall gold recovery was 89.6%. This overall recovery is close to the 93% overall gold recovery obtained with the pressure oxidation treatment of lower grade flotation concentrates.
- The production of high grade concentrates raises the possibility of avoiding the capital and operating cost of building a full scale pressure oxidation pre-treatment plant for the Duparquet Project. The capital cost of the POX circuit in the Tenova Bateman cost study, presented as part of the recent PEA, was $157.5 Million out of an estimated cost of $270 Million for the entire Mill. This cost would no longer be required but there would be some much lower additional costs for cleaner flotation, concentrate filtering, drying and shipping. Similarly, the operating cost for the POX area of the mill was estimated at $6.67/t of ore. This cost would not be required but would be substituted by the lower operating costs for concentrate preparation and shipping.
A rougher concentrate was recovered following the conditions applied in previous test work. In five out of six samples, only one cleaning stage was sufficient to produce concentrate grades exceeding 35 g/t in gold. Arsenic content averaged 1.1 % for the six samples and would imply a penalty since most smelters accept a 0.4% content.
The reagent consumptions for cyanidation of the flotation tailing were 0.14 - 0.47 kg NaCN/t of ore and 0.54 - 0.81 kg CaO/t of ore. These values are very low and indicate that cyanidation of the tailings will consume minimum amounts of chemical reagents.
Pre-Feasibility Study on the Duparquet Project:
Clifton Star has started a Pre-Feasibility Study on the Duparquet Project and part of it will compare the relative benefits of the two possible process treatments, either a POX circuit, as used in the PEA, or production of high grade gold concentrates.
Between January and March, Clifton has gathered a new 12 tonne sample of the Duparquet Project mineralized zones, from large diameter drill core. It was sent to SGS Lakefield for metallurgical and environmental pilot tests in support of the upcoming Pre-Feasibility Study. The planned test work will include a continuous pilot plant test for POX and also for high grade gold concentrates production. Tests are expected to be completed in the 2nd quarter of 2013.
Clifton Star will contact smelting companies and Commodity brokers to gauge the interest in toll treatment of the concentrates.
Qualified Person
Dr. David Dreisinger, P.Eng., F.C.I.M., F.C.A.E., is the Qualified Person (NI 43-101) who supervised the preparation of the technical information in this news release. Dr. Dreisinger is a Professor, and Chairholder of the Industrial Research Chair in Hydrometallurgy at the University of British Columbia (Vancouver, Canada) and a worldwide consultant for the metallurgical industry through Dreisinger Consulting Inc.
Investor Relations Consulting Agreements
By way of press release issued on September 17, 2012, Clifton Star announced that it had granted incentive stock options to six people, including 160,000 Options to two consultants performing investor relations activities. As disclosed in the September 17, 2012 release, the options may be exercised for a period ending on September 14, 2017 at a price of $1.14 per share. One quarter of the options vested on the grant date and the balance shall vest at a rate of 25% per six months period thereafter.
The Corporation wishes to inform that the consultants referred to in the September 17, 2012 release were Mr. Jerry Aie (100,000 options) and Rayna Consulting Services (60,000 options). Mr. Jesse Frederick is the principal of Rayna Consulting Services.
Furthermore, by way of press release issued on June 21, 2011, the Corporation announced that it had granted 35,000 incentive stock options, exercisable for a period ending on May 6, 2013 at a price of $4.15 per share, to a consultant of the Corporation. Clifton Star wishes to inform that the consultant referred to in the June 21, 2011, release was Mr. Jerry Aie.
The options referred to above are the only compensation to be paid by the Corporation for the investor relations services to be provided by Mr. Jerry Aie and Rayna Consulting Services. Both consulting agreements are for terms ending on September 14, 2014 and may be terminated by either party for any reason at its sole discretion upon giving the other party a thirty days prior notice.
Both Mr. Jerry Aie and Rayna Consulting Services are at arm's length with Clifton Star.