Gold-Ore owns the Bjorkdal gold mine through a wholly-owned Swedish subsidiary, Bjorkdalsgruvan AB. The assets of Bjorkdalsgruvan include exploitation concessions, all necessary environmental permits, a fully-operational gold concentrating plant, a tailings management facility, open pit and underground workings and associated mineral resources, and approximately 57 sq.km. of exploration concessions.
In early September, 2010 Bjorkdal produced its millionth ounce of gold!
RESOURCES (updated January 2011)
Mineral Resource Estimate - Tonnages and Grade
Resource
Type
Cut-off
Measured
Indicated
Measured + Indicated
Inferred
Au
(g/t)
Tonnage
(000's t)
Au (g/t)
Tonnage
(000's t)
Au (g/t)
Tonnage
(000's t)
Au (g/t)
Tonnage
(000's t)
Au (g/t)
Open Pit
0.30
349
1.47
9,932
1.18
10,281
1.19
10,435
1.07
Underground
1.00
1,943
2.75
4,248
2.60
6,191
2.65
2,736
2.91
Totals
2,292
2.56
14,180
1.61
16,472
1.74
13,171
1.45
Evaluation (2.5 m Selectivity) Adjusted for a 91% Mining Recovery and 30% Mining Dilution
Mineral Resource Estimate - Ounces
Resource
Type
Cut-off
Measured
Indicated
Measured + Indicated
Inferred
Au
(g/t)
Au
(Ounces)
Au
(Ounces)
Au
(Ounces)
Au
(Ounces)
Open Pit
0.30
16,500
376,800
393,400
359,000
Underground
1.00
171,800
355,100
527,500
256,000
Totals
188,300
731,900
920,900
615,000
Evaluation (2.5 m Selectivity) Adjusted for a 91% Mining Recovery and 30% Mining Dilution
RESERVES (to be updated by June 2011 based on new resource estimates above)
The economic parameters used for converting resources to reserves were based on actual operating conditions at Bjorkdal for the period December 2008 to August 2009 and are listed below:
Mechanized underground mining methods -- long hole stoping and lateral sub-level jumbo development
Open pit methods using blast hole drill rigs on 5 metre benches using standard truck and shovel excavation
Processing throughput of 3,200 tonnes/day for 350 days/year or 1.1 million tonnes per annum
Processing flow sheet includes crushing, grinding with gravity and flotation beneficiation to recover gold
Average plant recoveries at 90%
Refinery and smelter contracts established with payable gold at 94%
Average underground costs including mining, transportation, milling and G&A at Swedish krona $233 (US$ 29.20) per tonne
Average open pit costs including mining, transportation, milling and G&A at Swedish krona $110 (US$ 13.78) per tonne
Average Swedish krona to US dollar exchange rate (Dec 2008 to August 2009) at 7.98:1
LOCATION AND ACCESS
The Bjorkdal gold mine is located 30 km along paved highway northwest of the city of Skelleftea and 750 km north of Stockholm, Sweden. Skelleftea is a modern city of approximately 35,000 with daily flights to Stockholm. The area has a long history of mining and strong economic ties to the industry. Developed infrastructure includes railway and paved highways connecting the community to all of Sweden. Low cost hydropower and a skilled labour force further support the industry. The climate in this area of northern Sweden is moderated by the Gulf Stream and is very similar to Timmins, Ontario.
PROPERTY HISTORY
The Bjorkdal mine was discovered by Terra Mining AB by regional till sampling. The first anomalous gold values in till samples were found in 1983 and bedrock values were discovered in 1985. Definition drilling was started in early 1986; the feasibility study was finished in May 1987 and a production decision was made in July 1987. The first shipment of gold concentrate was made in September 1988.
Late in 1996, Williams Resources Inc of Toronto purchased Terra Mining and took over ownership of the mine. However, gold prices plummeted shortly thereafter and Williams placed the mine into receivership in June 1999. The property was dormant until 2001 when private concerns purchased the assets from the banks and started processing low grade stockpiles. Minmet acquired 50% of the mine in March of 2003 and the remaining 50% in October, 2003. Minmet extracted ore from the open pit during 2 brief periods in 2003 and 2004 and processed what was principally low grade stockpile material.
In 2006 Gold-Ore acquired an option from Minmet plc to purchase the holding company for the mine, Bjorkdalsgruvan AB, and on December 31, 2007 Gold-Ore exercised its option and acquired all the shares of Bjorkdalsgruvan AB. Bjorkdalsgruvan is now a wholly owned subsidiary of Gold-Ore.
GEOLOGY
The Bjorkdal mine is located in the eastern part of the Paleoproterozoic Skelleftea district. This 1.9 billion year old volcanic arc hosts close to 100 Zn-Cu-Au-Ag volcanic-hosted massive sulphide deposits (VHMS) of which 28 have been mined historically. The best known mine in this area is the famous gold-rich Boliden deposit which is located just 12 km from the Bjorkdal mine. The Skelleftea district consists of a lower volcanic sequence (Skelleftea Group) overlain by a younger sedimentary sequence (Vargfors Group). The 3 km thick Skelleftea Group is composed of mainly felsic volcanic rocks and the upper part of the Group hosts most of the VHMS deposits. The supracrustal rocks of the Skelleftea District were later cut by a variety of intrusions.
The gold at Bjorkdal is associated with centimetre to metre wide subvertical quartz veins within a biotite-altered granodiorite. The gold mineralization is localized near the contact between the intrusive and the overlying Skelleftea Group. The veins mainly trend NE and NNE and terminate at the sediment-intrusive contact. The gold is found both as free milling gold and also associated with pyrite.
The Bjorkdal mine belongs to the class of gold deposits known as "Intrusion Related Gold Systems" or IRGS. This class of deposits includes some new multi-million deposits such as the Fort Knox mine (6.7 Moz Au), Pogo (5.1 Moz Au), Donlin Creek (23 Moz Au) and Dublin Gulch.
PROCESSING PLANT
The processing plant at the mine, which operates at a capacity of 3,200 tonnes per day, was built in 1988 and has been well maintained. The plant consists of a coarse crusher, a rod and ball mill, gold gravity concentration circuit (including a Knelson concentrator) and flotation circuit for gold bearing pyrite. Feed material is sourced from underground, open pit and stockpiles. Gold recoveries average almost 90%. The tailings from the plant are very benign, containing no deleterious material, and have been classified by Swedish authorities as non-toxic.
MINING METHODOLOGY
Underground
The gold-bearing veins at Bjorkdal range from less than one metre to six metres in width and commonly occur as swarms. The veins are vertical and the granodiorite host rock is extremely competent. The underground mining method being utilized is longhole stoping or blast hole open stoping with sub-level spacing of 20 metres. This mining method has been used successfully in many different mines throughout the world.
Using this mining method a gold bearing vein is developed with sublevels driven along the vein. The six veins planned for testing in our initial exploration program all showed gold bearing zones, with good lateral continuity that varied in width from 3 meters wide to 6 meters wide, and in length anywhere from 15 meters long to 110 meters long. These zones are being divided into mining blocks, or stopes, with a maximum strike length (distance along the vein) of 30 meters. Wherever the gold bearing zone is longer than 30 meters, it is divided into blocks with a maximum length of 30 meters leaving a small unmined pillar between each block.
A typical 30 metre block 3 metres wide is mined as follows. An upper, (drilling) sublevel is driven 3 metres wide by 4 metres high on vein 20 metres above the lower, (mucking) sublevel, which is the same size and is driven on same vein directly below the drilling sublevel. At the far end of the drilling sublevel a production drill drills a slot raise, or initial hole, that is drilled between the bottom of the drilling sublevel to the top of the mucking sublevel. Because the sublevels are 20m apart the production drill holes are 16 metres long. Behind the slot raise the production drill drills lines of blast holes until the 30 metres long block is completely drilled.
When drilling is completed the slot raise is blasted. The slot raise is blasted retreating upwards in a series of blasts that remove between 2 and 5 vertical meters of the raise with each blast. The broken rock is removed after each blast via the mucking sublevel using a scooptram (a low profile front end loader). Once the muck from the slot raise is removed the production drill lines are blasted into the void produced by the slot raise. These lines are blasted in groups of 3 to five lines with enough muck removed between blasts to allow sufficient void for the following blast. When the entire mining block is blasted the scooptram mucks out the remaining broken ore. The scooptram is fitted with a remote control to allow mucking of material beyond the blasted brow during the final clean up.
By leaving small pillars, and changing the mining sequence, this mining method can be adapted to changing ground conditions, and can be modified to drill production holes either down towards the mucking sublevel as described, or up towards a previously developed sublevel or known mining boundary.
For more detailed information on Bjorkdal see "Technical Reports"
