The company said that recent tests from SGS Lakefield Research showed high gold recoveries from mineralization at the project are possible, using a combination of conventional flotation, pressure oxidation and cyanidation.
A significant amount of gold is locked in refractory sulfide minerals, therefore refractory sulfide ores are generally treated by pre-oxidation prior to recovery of gold by cyanidation.
The overall average gold recovery from six metallurgical samples from the Duparquet project gold zones was 93 percent. Six metallurgical samples, with head grades ranging from 1.25 grams per tonne (g/t) gold to 3.58 g/t gold, were provided to SGS Lakefield Research for gold recovery testing.
"It has been commonly considered that the resource at Duparquet may be difficult to treat from a metallurgical stand point, "said president and CEO Michel Bouchard. "Considering the tests results, the uncertainty is largely lifted."
The company said the average sulfide oxidation for the best test for each of the six samples was 98.8 percent.
The core samples were taken from the Beattie, the Donchester North, the Donchester South, and the Central Duparquet Main Zone. A sample of the historical tailings from Beattie was also tested, Clifton Star added.
Arsenic levels were low in all six samples, meaning environmental control of arsenic will be "straightforward" at these levels.
Despite the positive results, in order to determine the most "economical process to treat the mineralization", samples of bulk concentrate were provided to Goldfields of South Africa for testing using the BIOX technology as an alternative to pressure oxidation.
The BIOX process uses bacteria to catalyze the oxidation of pyrite and arsenopyrite prior to gold recovery by carbon-in-leach cyanidation.
Samples of bulk concentrate were also sent to Australia for testing the Albion process, which uses fine grinding and neutral oxidation of pyrite and arsenopyrite prior to gold recovery by carbon-in-leach cyanidation.
Both series of tests have started, with Clifton expecting to have preliminary results in June of this year.
On Thursday, Clifton Star announced the results of its 2011 drill program at its Duparquet project, which is located along the prolific Destor-Porcupine fault in the Abitibi region of Quebec.
In 2011, Clifton Star drilled 85 holes, totaling 26,754 metres. The drill program focused on the Beattie, Donchester, and Central Duparquet properties.
Significant results from the North zone included hole BD10-277, which intersected 2.06 grams per tonne (g/t) gold over 58.3 metres; hole BD10-270, which hit 2.25 g/t gold over 36.0 metres; and hole D11-149, which intersected 32.3 metres grading 1.66 g/t gold.
At the North zone, gold mineralization has been traced along strike in an east-west direction for 2.6 kilometres.
The company said it will incorporate the 2011 data into a comprehensive NI 43-101 compliant resource estimate for the Duparquet project. The report, which is expected for completion in April 2012, is currently being prepared by InnovExplo, a mining consultation firm in Val-d'Or, Quebec.
The report will form the basis of a preliminary economic assessment.
Earlier this week, the company filed an updated NI 43-101 resource report for its Donchester property. A previous technical report on Donchester from June 2011 was deemed non-compliant with the requirements of NI 43-101 by the British Columbia Securities Commission (BCSC), prompting a cease trade order on Clifton Star's stock.
The latest report gave an inferred resource of 11.01 million tonnes with an average grade of 3.06 grams of gold per tonne for 1.05 million contained gold ounces, at a cut-off grade of 1.5 grams of gold per tonne, and using a top-cut of 8.0 grams per tonne.
The company also said Thursday it currently has two active drill rigs at the Beattie and Donchester properties, completing a 20-hole program.
The drilling will primarily focus on the continued surface exploration of the various zones at the Beattie, Donchester, Dumico, and Central Duparquet properties, in order to better define the limits of the known mineralization between 400 and 600 metres below surface, as well as to identify the limits of higher grade sections within the known zones.