EXPLANATORY NOTE to the feasibility report on development of gold deposit "Venus Mine“ Yukon Territories
The given feasibility report is executed by the following group of experts: engineer-geologists PhD of Geology Anvar Baymuhamedov, Dina Ermekbayeva, the mining engineer PhD of Technical Science Lolita Kakharova under a management and with participation of professor Abrol Kaharov under the task coordinated with the owner of deposit Ron Berdahl, during the period of August 15, 2004 -January 15, 2005.
The purpose of research consists in definition of economic efficiency of an opportunity of gold deposit "Venus Mine" development in view of technical requirements of mineral resources development in defined conditions and a modern economic situation in the market of base metals and gold in the world. As a basis of the analysis and evaluations have been accepted the reserve calculations carried out in 1967-1985 and submitted by the prospecting organization.
During the work the geological information, reporting data of Mining Recorder''s Office.
Authors express the gratitude and thank the Chief Geologist of the Yukon Government Mike Burke and Ron Berdahl for the help during studying of the data of the deposit and others in Territory Yukon, and also for valuable advice during the compiling of the feasibility report.
2.History of mining on gold deposit "Venus Mine" Yukon Territory.
(Work history)Venus Vein system was staked in Sep/01 by J.M.Pooley, A.B. Palmer & J.M. Stewart as Venus,Uranus, etc. (3768) and was transferred in 1905 to Conrad Cons. The About 1830 tones were mined in 1920, shipped 1556 tones of high grade ore worth $120 000 and 03 tones of concentrate worth $26 000, according to one report. C.E.G. Brown estimated in 1963 that 2450 tones averaging 21.9 g/t Au and 2338.2 g/t Ag were shipped between 1910 and 1920. Red Deer and Humper veins, were mostly staked in 1904-06 and were known as the Dail-Fleming group.
From 1906-08, by Conrad Cons ML briefly in 1908, and by Caribou Mg CL in 1917. They were explored with at least five adits and three shafts. In 1922, Maybell MC put in a 975 m adit on the Maybelle fraction adjoining the Venus Mine.
In 1928, Yukon Gold Co acquired the Venus Extension, the Ray cl (19024) and Peggy cl (19023) but did little work.
Between 1940 and 1960, the property was consolidated by the Tagish Lake Synd, which sold it in 1966 to Venus ML. Venus built a road from Carcross, completed 2059 m of drifting, 387.7 m of raising and 2191.8 m of u.g. drilling from two adit levels (2700 ft and 2600ft). Production commenced in Sep/70 and by Jun/71, when the mine was closed because of poor recoveries (68% Au, 79% Ag, 84% Pb & 73% Zn) and heavy losses, the mill had treated 58 900 tonnes grading 5.8 g/t Au, 181.7 g/t Ag, 3.7% Pb and 2.5% Zn.
Between Oct/80 and Oct/81, about $9 million was spent on construction of a new 91 tonne/day mill, 10 km south of the adit, but production was deferred because of low metal prices. In Aug/87 by J.B. O''Neill & R. Hilker.
A feasibility study on remediation of the mine tailings was planned in summer 1994 under the Federal Arctic Environmental Strategy. In the summer of 1995 the tailings were partially dug up and then sealed in a clay liner. In Aug/95 Raindrop cl 1-2 (YB06940) were tansferred in trust to the Carcross First Nation as partial settlement of their land claim. In Jul/97 J. O''Neil staked Venus fraction (YB97803) adjacent to the occurrence. In Sep/97 B.Scott staked Au (YC08183) 2.5 km to the north, along the shore of Windy Arm Lake.
3. Geology of deposit "Venus Mine"
Most of the development has been on the main Venus vein, a north-trending, shallowly westdipping, quartz fissure vein system which cuts intermediate volcanic rocks of Cretaceous age. The vein has been traced for more than 1.6 km on surface along a steep mountainside overlooking Tagish Lake. Fourteen other veins are present but most have not been explored. The 2700 adit is located 760 m southwest of the original mine on the Venus #2 claim, while the 2600 adit is 365 m northeast of the 2700 adit. The Red Deer vein is located farther uphill to the west, and strikes more northeasterly, whereas the Humper Vein is situated at the south end and strikes easterly.
The Venus vein, which is the strongest structure on the property, ranges from about 8 cm to 2.4 m wide. Mineralization consists of coarsely crystalline quartz and carbonate carrying irregular bands and pods of pyrite, arsenopyrite, galena and sphalerite with minor tetrahedrite and chalcopyrite.
Mineralization on the other two veins was reportedly similar in composition. Twelve ore shoots ranging in length from 14 to 42 m were sampled by Venus ML and gave an average grade of 13.4 g/t Au, 396.0 g/t Ag, 2.6% Pb, 1.7% Zn & 0.09% Cd across a minimum width of 1.2 m.
At the start of production, ore reserves were calculated at 68 466 tonnes proven and 53 865 tonnes probable. After the mine closed, remaining reserves were recalculated as 54 364 tonnes proven and 16 017 tonnes probable averaging 9.26 g/t Au, 247 g/t Ag, 2.1% Pb and 1.4% Zn across a 1.5 m mining width. Operational problems were blamed on insufficient cutting of high assays, dilution caused by the flat dip, and poor gold recoveries from arsenopyrite because the cyanide circuit never reached full operation.
Resampling and further exploration drifting and drilling by United Keno Hill Mines Ltd extended mineralization to 170 m below the 2 600 level and led to the calculation of new reserve figures in Jun/80. These figures indicated proven reserves of 54 354 tonnes, probable reserves of 16 017 tonnes and > >indicated reserves of 38 329 tonnes, grading 7.55 g/t Au, 226.3 g/t Ag, 1.89% Pb and 1.37% Zn.
The 1984 work on the Venus Vein increased proven reserves to 61 689 tonnes grading 10.98 g/t Au, 305.14 g/t Ag, 2.5% Pb and 1.5% Zn. These figures do notinclude 12 156 tonnes of ore grading 5.83 g/t Au, 147.43 g/t Ag, 1.3% Pb and 0.7% Zn stockpiled at the Venus mill site.
The 1984 drilling on the Uranus Vein outlined a zone 50 m long averaging 3.8 g/t Au, 870.8 g/t Ag, 5.7% Pb and 2.6% Zn across 1.5 m. The paragenesis can be divided into two stages: (1) early quartz-arsenopyrite-pyrite; and (2)late quartz-sphalerite-galena- - Au. Gold occurs with galena primarily as fracture fillings in arsenopyrite. Steeply dipping ore shoots, which are not visually apparent, comprise 20% of the veins and typically contain both types of mineralization.
The wallrocks are altered to a sericitecarbonate-quartz-pyrite assemblage with local pods of intense clay alteration. A rare hydrous arsenite of iron and calcium was identified here in 1913 by Tyrrell Graham and named Yukonite.
4. The initial data for compiling the feasibility report for gold deposits " Venus Mine "
The Goal: to define the basic directions of development and technical parameters of processing, parameters of economic efficiency of 1st line of a mine.
The reserves of gold, silver, lead and zinc in Venus Mine deposit as in 1984 is:
1. Reserves of ore - 61 689 tons. 2. The average grade of gold in ore - 10.98 g/t 3. The average grade of silver in ore - 305.14 g/t 4. The average grade of lead in ore - 2.5 %. 5. The average grade of zinc in ore - 1.5 %
Also the data from previously made Feasibility Study and Project Base Study on Venus Mine deposit have been analyzed and taken into consideration.
Furthermore volume of ore previously extracted and stockpiled in the area is accounted:
1. Reserves of ore - 12 156 tons. 2. The average grade of gold in ore - 5.83 g/t 3. The average grade of silver in ore - 147.43 g/t. 4. The average grade of lead in ore - 1.3 %. 5. The average grade of zinc in ore - 0.7 %
Without going in details of the analysis of practice and Feasibility Study of Venus Mine in the past, it is necessary to note that estimated economic parameters of the project efficiency appeared today unsuitable because of noticeable change of world market prices of gold and base metals, and also practice of primary development of the deposit, revealed high degrading of ores during excavation and low recovery of gold with high losses into tailings during processing.
Also were problematic qualitative-quantity properties of arsenic in ore and concentrates. These and other production-economics indices of work practice were the reason for a cessation of work on this mine.
In the given work when compiling the production-economics project are considered: reliability of the grade of gold in th