In 1972, the first gold was discovered at the Jerritt Canyon District, with the first gold poured on July 4, 1981. Open pit mining occurred between 1981 and 1999. Portal-accessed, underground mining commenced in 1993 with the SSX-Steer Complex and the Smith mine. Since mining began, Jerritt Canyon has produced over 7 million ounces of gold.
Operations
None of the Jerritt Canyon mines exceed 1,000 feet in depth measured from the elevations at their portals. Underground mining uses low-profile 6-cubic-yard load/haul/dump tractors (LHD) loading 35- and 40-ton trucks for ore removal. Ground support typically uses rock bolts and shotcrete, with cemented back-fill in mined-out areas.
All underground ore is stacked near the mine portals for grade sampling. It is then transported in 150-ton haul trucks to the mill. Due to the sulfide refractory nature of Jerritt Canyon's ore, the mill feed is dried and roasted and gold is recovered using conventional carbon-in-leach processing. High quality gold doré bars are then shipped for commercial refining and sale.
The information provided about Jerritt Canyon on this portion of the Company's website has been reviewed and approved by the Company's Senior Geologist and Qualified Person, Todd Johnson (M.Sc.).
SSX - Steer Complex
Mining Method
Conventional sublevel stoping
Blind bench stoping
Ramp bench stoping
Blind uphole stoping
The drift connecting the SSX and Steer mines was completed in late 2005, and the two mines are now referred to as the SSX-Steer Complex. By providing a secondary escape way and ventilation, this connection allowed commercial production from Steer to begin in 2005. The drift also allows the SSX-Steer deposits to share infrastructure in order to optimize production. The SSX- Steer connection also enables drill platforms to explore this prospective corridor.
The SSX deposit was discovered in the early 1990s following the structural trends between the Burns Basin and California Mountain deposits. Mining commenced in 1997. The deposit occurs 450 to 1,000 feet below the surface. It has been in the last few years the main gold producer at Jerritt Canyon. The SSX deposit is primarily structurally controlled by a network of northwest (e.g. South Boundary Fault, South Saval Trend), and northeast (e.g. Purple Fault, Saval Fault) structures. The intersection of the northeast and west-northwest structural trends remain a primary target for resource expansion. The westward extension of the South Boundary Dike and the Mahala resource to the east represent exploration opportunities.
Gold mineralization in the Steer portion of the SSX- Steer Complex has been identified in an area stretching approximately 3,000 feet east from the old Steer pit to halfway along the connection drift to SSX Zone 5. In the eastern portion of the Steer area, high-grade mineralization is associated with the Husky fault. The intersection of these dikes with the Hansen III unit and the Husky fault and its related structures offer excellent exploration potential.
The following tables show 2008 underground exploration drill hole results from the SSX-Steer Complex and the Smith Mine at the Jerritt Canyon property.
Don Colli (P.Geo.) former Manager of Mine Geology for Queenstake Resources, compiled and reviewed the aforementioned drill results table that were received before June 30, 2008. Todd Johnson, M.S., VP of Exploration with Veris Gold Corp. and a qualified person as defined by NI 43-101, has reviewed and verified the technical information contained in this table as applicable.
The qualified person for the aforementioned data is Todd Johnson (M.S. Geology; M.S. Geological Engineering) who is the current VP of Exploration with Veris Gold Corp.
Smith
Mining Method
Conventional sublevel stoping
Blind bench stoping
Ramp bench stoping
Blind Uphole Stoping
The Smith Mine, accessed via a portal from the Dash open pit, was started in 1999 as the pit was being mined out. The Smith Mine complex consists of several mineralized areas that are accessed from the Smith portal, as well as East Dash to the east that will be accessed from a separate portal in the Dash pit.
Gold mineralization in the main Smith, Mahala and West Dash deposits is associated with the northeast trending Coulee Fault and west-northwest trending faults and dikes. In Zone 1, high-grade gold mineralization is hosted in the upper and middle portions of the Hansen Creek III unit within a northwest trending horst block between the South Graben fault and the 170 fault. Mineralization in Zones 2 and 3 is directly associated with west-northwest trending dikes. High-grade mineralization occurs within the Hansen Creek II and III units along the steeply dipping dikes.
Gold mineralization in the Mahala area is spatially associated with the west-northwest trending Mahala fault and associated dikes and favorable ore-host stratigraphy, including the Hansen Creek Formation and lower beds of the Roberts Mountains Formation. Mineralization at East Mahala occurs primarily in broad, Southeast-dipping lenses in the hanging wall of the Coulee Fault.
The West and East Dash deposits occur at the ends of the west-northwest trending Dash Fault system which formed the mineralization mined in the Dash pit. The West Dash deposit occurs at the intersection of the Coulee fault and the west-northwest trending Dash fault. West Dash is accessed through the Smith Portal. The East Dash deposit lies to the east of the Dash pit and will be accessed by a separate portal in the pit. At East Dash, most gold occurs in two lenses parallel to the Dash Fault and dipping to the northeast.
The following table shows the 2011 underground exploration drill hole results from the the Smith Mine at the Jerritt Canyon property.
Data Compiled by William Hofer, Chief Geologist at Jerritt Canyon for Queenstake Resources. The drill results have been reviewed and authorized for release by Todd Johnson, the Qualified Person, as per NI 43-101 guidelines.
Recovery Process
The mineral processing operation at Jerritt Canyon is one of only three processing plants in Nevada that uses roasting in its treatment of refractory ores. Initially, Jerritt Canyon was designed to process oxide and mildly refractory gold ores. In 1989, the roasting circuit was added to the process for the treatment of highly refractory ores which are now being mined and processed at Jerritt Canyon.
The unit operations at the Jerritt Canyon processing plant are comprised of the following circuits:
Primary crushing;
Secondary crushing;
Fine ore drying;
Tertiary crushing;
Dry grinding;
Roasting;
Carbon-in-leach ("CIL") with cyanidation and carbon adsorption;
Carbon stripping;
Carbon reactivation;
Electro-winning;
Precipitate refining;
Oxygen plant;
Water evaporation pond; and
Tailing impoundment.
Reserves & Resources
Summary Table 1. Jerritt Canyon Mineral Reserves: December 31, 2011
Proven
Probable
Total Proven + Probable
Deposit/Mine
K tons
oz/st
K oz
K tons
oz/st
K oz
K tons
oz/st
K oz
Under- ground
Murray
106.0
0.213
22.5
306.4
0.224
68.6
412.4
0.221
91.1
Saval
19.7
0.229
4.5
149.3
0.207
31.0
169.1
0.210
35.5
Smith
955.9
0.206
197.3
1,100.7
0.217
238.4
2,056.6
0.212
435.7
SSX
598.5
0.192
115.1
682.4
0.189
129.2
1,280.9
0.191
244.4
Starvation
6.0
0.271
1.6
337.4
0.265
89.3
343.4
0.265
90.9
W. Mahala
23.5
0.214
5.0
175.9
0.185
32.5
199.3
0.188
37.5
UG Reserve Subtotal
1,709.6
0.202
346.1
2,752.1
0.214
588.9
4,461.7
0.210
935.0
Open Pit
Burns Basin
45.7
0.093
4.2
303.1
0.076
23.0
348.8
0.078
27.2
Mill Creek
3.2
0.089
0.3
182.9
0.090
16.5
186.0
0.090
16.8
Saval
36.9
0.172
6.3
108.1
0.065
7.0
144.9
0.092
13.4
Wright Window
4.9
0.175
0.9
108.0
0.093
10.0
112.9
0.096
10.9
Subtotal
90.6
0.129
11.7
702.0
0.080
56.5
792.6
0.086
68.2
Stockpiles
180.0
0.094
17.0
622.6
0.065
40.7
802.6
0.072
57.7
Total All Sources
1,980.2
0.189
374.8
4,076.7
0.168
686.0
6,056.9
0.175
1,060.8
Notes:
the following parameters were used to determine the gold cutoff grade for each reserve area: a US$1,275 per oz gold price which is equal to the 36-month trailing average; Grade dependent metallurgical gold recoveries ranging from 75% to 90%;
all of the December 31, 2011 underground mineral reserves are presented using a 0.12 opt Au cutoff grade except for Starvation Canyon which used a 0.13 opt Au cutoff grade;
the December 31, 2011 open pit mineral reserves used cutoff grades ranging from 0.044 to 0.047 opt Au;
the December 31, 2011 reserves are contained entirely within designed underground or surface mine excavations;
mineral reserves were determined by Mark Odell, P.E., Practical Mining LLC.
Table 2. Jerritt Canyon Measured and Indicated Mineral Resources, Including Reserves: December 31, 2011
Measured
Indicated
Total Measured + Indicated
Deposit /Mine
K tons
oz/st
K oz
K tons
oz/st
K oz
K tons
oz/st
K oz
Under- ground
Calif. Mtn.
-
-
-
4.5
0.184
0.8
4.5
0.184
0.8
Murray
163.0
0.207
33.7
427.2
0.216
92.2
590.2
0.213
125.9
Saval
55.9
0.237
13.2
277.7
0.222
61.5
333.6
0.224
74.8
Smith
2,098.1
0.224
470.2
2,133.4
0.215
458.6
4,231.5
0.220
928.8
SSX
2,248.2
0.211
474.0
1,451.1
0.205
298.2
3,699.2
0.209
772.2
Starvation
5.9
0.294
1.7
519.4
0.25
130.0
525.2
0.251
131.8
W. Mahala
25.3
0.196
5.0
363.5
0.190
68.9
388.7
0.190
73.9
Winters Ck.
-
-
-
90.3
0.162
14.6
90.3
0.162
14.6
Subtotal
4,596.3
0.217
997.9
5,267.0
0.214
1,124.9
9,863.3
0.215
2,122.8
Open Pit
Burns Basin
34.5
0.087
3.0
309.9
0.097
30.2
344.5
0.096
33.2
Mill Creek
3.2
0.091
0.3
272.9
0.094
25.8
276.2
0.094
26.1
Pie Creek
-
-
-
205.4
0.087
17.9
205.4
0.087
17.9
Road Canyon
-
-
-
17.5
0.069
1.2
17.5
0.069
1.2
Saval
84.8
0.135
11.4
569.5
0.065
37.2
654.3
0.074
48.6
Wright Window
7.9
0.142
1.1
117.8
0.090
10.6
125.8
0.094
11.8
Subtotal
130.4
0.121
15.8
1,493.1
0.082
122.9
1,623.6
0.085
138.7
Stockpiles
180.0
0.094
17.0
622.6
0.065
40.7
802.6
0.072
57.7
Total All Sources
4,906.8
0.210
1,030.7
7,382.7
0.175
1,288.5
12,289.5
0.189
2,319.2
Notes:
the resource cutoff grades were calculated in a similar manner as the reserve cutoff grades except that a US$1,400 per oz gold price was used which is equal to a 24-month trailing average gold price;
the SRK 2008 open pit resources were verified and/or modified as part of this study and were calculated using variable cutoff grades from 0.068 opt to 0.086 opt Au at lower gold prices ($450 to $550 per oz);
the December 31, 2011 underground mineral resources are presented using a 0.11 opt Au cutoff grade except for Starvation Canyon which was calculated using a 0.12 opt Au cutoff grade;
the open pit resources used cutoff grades ranging from 0.039 to 0.043 opt Au and are constrained by a Lerch Grossman pit shell;
the December 31, 2011 underground resources were only tabulated if the estimated blocks were inside the modeled Au grade shell and greater than 0.120 opt Au, are accessible from existing or planned excavations, and they were deemed recoverable with respect to their overall size and location relative to the existing workings by the qualified person.;
mineral resources that are not mineral reserves do not have demonstrated economic viability; and
mineral resources determined by Mark Odell, P.E., Practical Mining LLC.
Table 3. Jerritt Canyon Inferred Mineral Resources: December 31, 2011
Inferred
Deposit
/Mine
K tons
oz/st
K oz
Underground
California Mtn.
29.5
0.192
5.7
Murray
86.0
0.215
18.5
Smith
979.5
0.196
191.8
SSX
371.7
0.198
73.7
Saval
95.4
0.200
19.1
Starvation
255.4
0.253
64.6
West Mahala
1,854.6
0.175
324.0
Winters Creek
9.2
0.186
1.7
Underground Subtotal
3,681.2
0.190
699.1
Open Pit
Burns Basin
14.0
0.079
1.1
Mill Creek
3.4
0.154
0.5
Pie Creek
4.9
0.090
0.4
Road Canyon
185.1
0.082
15.1
Saval
222.2
0.142
31.6
Wright Window
4.8
0.093
0.4
Open Pit Subtotal
434.5
0.113
49.3
Stockpiles
-
-
-
Total Inferred Resources
4,115.7
0.182
748.4
Notes:
Similar resource tabulation methodologies described for Table 2 above apply to the resources in Table 3;
Mineral resources that are not mineral reserves do not have demonstrated economic viability; and
mineral resources determined by Mark Odell, P.E., Practical Mining LLC.
The 2011 Jerritt Canyon mineral resources were estimated by Mark Odell, P.E. and Owner of Practical Mining LLC, who is the independent Qualified Person for the December 31, 2011 Mineral Resources and Reserves as defined by NI 43-101. Practical Mining LLC is preparing an updated NI 43-101 Technical Report which will include these new resource and reserve results that will be separated by open pit and underground mining methods.
The mineral resources have been estimated in accordance with the standards adopted by the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Council in August 2000, as amended, and prescribed by the Canadian Securities Administrators' National Instrument 43-101 Standards of Disclosure for Mineral Projects.
Yukon-Nevada Gold Corp. has filed on www.sedar.com a National Instrument 43-101, a compliant technical report entitled "NI 43-101 Technical Report Update, Yukon-Nevada Gold Corp., Jerritt Canyon Property, Elko County, Nevada, USA," dated June 28, 2011, encompassing the mineral reserves discussed herein, which includes further details with respect to the reserves and resources. That report can be found here: NI 43-101 Technical Report Update, Yukon-Nevada Gold Corp., Jerritt Canyon Property, Elko County, Nevada, USA
Exploration and resource conversion drill hole samples collected from the Jerritt Canyon property are delivered to and analyzed by ALS Laboratory Group in Reno, Nevada using standard fire assay techniques whereas production drill holes are delivered to and analyzed by the Jerritt Canyon Mine assay lab. The Company's 2010 Sampling Methods, and Sample Preparation and Analyses, and Quality Assurance and Quality Control protocols are described in Sections 10 and 11 of the April 27, 2012 Jerritt Canyon Property NI 43-101 Technical Report.
Mr. Johnson has verified the mineral resources and reserves stated above in Tables 1, 2, and 3 and has approved them for use in this presentation.
Cautionary Note to U.S. Investors concerning estimates of Measured, Indicated and Inferred Resources
This document uses the terms "measured and indicated resources". The Company advises U.S. investors that while these terms are recognized and required by Canadian regulations, the SEC does not recognize them. U.S. investors are cautioned not to assume that any part or all of mineral deposits in this category will ever be converted into reserves.
This document also uses the term "inferred resources". The Company advises U.S. investors that while this term is recognized and required by Canadian regulations, the SEC does not recognize it. "Inferred resources" have a great amount of uncertainty as to their existence, and great uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of an inferred mineral resource will ever be upgraded to a higher category. Under Canadian rules, estimates of inferred mineral resources may not form the basis of a feasibility or other economic study. U.S. investors are cautioned not to assume that any part or all of an inferred resource exists or is economically or legally minable.
Mineral Reserve Terminology: Canadian and U.S. Differences
The Company is organized under the laws of British Columbia, Canada. The mineral reserves and resources described here are estimates and have been prepared in compliance with National Instrument 43-101 of the Canadian Securities Administrators. The definitions of proven and probable reserves used in National Instrument 43-101 differ from the definitions in the United States Securities and Exchange Commission ("SEC") Industry Guide 7.
Exploration Overview
District Geology
The Jerritt Canyon deposits are typical of the Carlin-type deposit of micron to submicron-sized gold particles hosted primarily by carbonaceous, Paleozoic calcareous and sulfidic sedimentary rocks. Lesser amounts of ore are hosted by intermediate to mafic intrusive rock. The deposits often consist of several discrete pods or zones of mineralization whose location is controlled by intersections of major west-northwest and north-northeast structures that cut folded, permeable and chemically favorable host rocks. Locally, intrusive dikes that follow the northwest or northeast structures may be important host rocks. The combination of these structural and stratigraphic controls imparts a highly irregular shape to the ore zones, although most have more horizontal than vertical continuity depending upon the orientation of the host rocks. Gold in the Jerritt Canyon ore deposits occurs as free particles of intergranular, native gold, on or within pyrite, or in association with sedimentary carbonaceous material. Due to the sulfide and carbonaceous affinities, most of the gold deposits at Jerritt Canyon require fine grinding and oxidation to permit the gold particles to be liberated by standard, carbon-in-leach cyanidation.
Project Drilling
Exploration drilling programs typically consist of reverse circulation (RC) drilling at about 200-foot centers. The spacing is then reduced to about 140 feet and finally, to 100-foot centers or less. Surface core drilling will also augment the drilling programs. At the underground mines, definition drilling usually consists of core drilling on 50-foot centers from underground stations. Underground RC drilling (Cubex) is typically used for resource conversion and is drilled on 20- to 40-foot centers.
Tens of thousands of holes have been drilled on the Jerritt Canyon property over the years. The Murray Mine has over 22,000 holes with more than 2 million feet drilled; the Smith mine has over 5,000 holes with more than 1.25 million feet; the SSX mine has nearly 16,000 holes with 2.4 million feet of drilling.
The following table shows 2011 surface exploration drill hole results from open pit targets at Jerritt Canyon.
The information contained in this news release has been reviewed and approved by the Company's Vice President of Exploration, Todd Johnson, M.Sc. (Qualified Person per the requirements of NI 43-101).
The following table shows additional 2011 surface exploration drill hole results from the West Mahala Project at Jerritt Canyon.
The information contained in this news release has been reviewed and approved by the Company's Vice President of Exploration, Todd Johnson, M.Sc. (Qualified Person per the requirements of NI 43-101).
The following table shows the 2011 surface exploration drill hole results from the Mahala Project at Jerritt Canyon.
The information contained in this news release has been reviewed and approved by the Company's Vice President of Exploration, Todd Johnson, M.Sc. (Qualified Person per the requirements of NI 43-101).
The following tables show 2008 surface exploration drill hole results from throughout the Jerritt Canyon property.
Todd Johnson, M.S., VP of Exploration with Veris Gold Corp. and a qualified person as defined by NI 43-101, has reviewed and verified the technical information contained in this table as applicable.
The qualified person for the aforementioned data is Todd Johnson (M.S. Geology; M.S. Geological Engineering) who is the current VP of Exploration with Veris Gold Corp.
Starvation Canyon
The discovery of high-grade mineralization at Starvation Canyon has been particularly exciting, as this is the first substantial gold deposit found in the southern part of the district - an area considered to have similar geologic structures as the mines in the northern part. The mineralized zones that host the Starvation Canyon deposit are mostly classified as indicated resources in the December 2007 reserve estimate. The thickness and grade of mineralization are comparable to the mineralization found previously at Jerritt Canyon.
Starvation Canyon is located on private land owned by Queenstake in the southwestern part of the Jerritt Canyon District. The gold mineralized zone at Starvation Canyon lies above the water table in the area of steep topography and could be easily accessed by portal from the hillside.
Starvation Canyon drilling has identified a prospective 4 1/2-mile mineralized trend that includes Starvation Canyon and mineralized targets at Waterpipe II and Pie Creek. The northwest structure that appears to be the primary control for the Starvation Canyon resource could hold potential for additional clusters of mineralization both to the northwest and southeast.
The following table show the 2011 surface exploration drill hole results from the Starvation Project at Jerritt Canyon.
The information contained in this news release has been reviewed and approved by the Company's Vice President of Exploration, Todd Johnson, M.Sc. (Qualified Person per the requirements of NI 43-101).
Exploration History
The Jerritt Canyon district was originally explored by prospectors looking for antimony in the early 1900s. FMC Corporation, exploring for antimony in the 1970s, discovered gold occurrences similar to those in the nearby Carlin trend. In 1976, FMC, then known as Meridian Mining, formed a joint venture with Freeport Minerals to explore and develop the deposits. Mining commenced in 1981 at Jerritt Canyon with the North Generator open pit.
Since then, the operators of Jerritt Canyon conducted exploration programs for the identification and development of new mineralized areas. The Jerritt Canyon operation has had a history of exploration and discovery since the 1970s. Historically, most of the exploration efforts were concentrated at and around the existing underground mines in the northern part of the district. Several open pit deposits were discovered, developed and mined during the 1980s and 1990s, including North Generator, Alchem, Marlboro Canyon, Burns, Steer, Saval and Dash. Underground targets were also identified, and the first to be exploited was the West Generator underground deposit in 1993. The MCE, Smith and Steer deposits were more recent discoveries. The million-ounce Murray Mine unexpectedly was discovered by drilling an area being prepared for surface support facilities. The SSX deposit was discovered in the early 1990s by geologists following the structural trends between Burns Basin and California Mountain open pits. The SSX Mine produced its millionth ounce of gold in 2005, becoming the fifth millionth-ounce mine at Jerritt Canyon.
The first gold reserves from the Starvation Canyon project and Mahala Basin were delineated in 2005 and added to in 2006 and 2007. Additional drill holes targeting previously identified indicated resources at West Mahala, as identified in the 2008 43-101 report, and other mineralization at the Mahala Basin are warranted in the future. The resources at West Mahala lie within 900 to 2900 feet to the existing underground development at the SSX-Steer Complex. Exploration opportunities are plentiful throughout the entire Mahala Basin area as evidenced from the 2007 and 2008 exploration drilling results.
Exploration drilling recommenced at Smith Mine as of June 12, 2010 and is continuing today. A 130,000 foot surface drilling program was completed in 2011 that tested projects throughout the property. Modelling of the recently aquired drill hole data is in progress to update the mineral and resources of the district.