Orex Exploration is a former Canadian gold mining company that conducted exploration work on mining properties it owned in the Goldboro and Guysborough County areas of Nova Scotia.[3][4] The properties owned by Orex were the sites of the former Boston Richardson Mine, Dolliver Mountain Mine, West Goldbrook Mine, and East Goldbrook Mine which operated between 1892 and 1912. Headquartered in Rouyn-Noranda, Quebec, the company was founded in 1987 and raised funds for exploration work, in part, by issuing stocks traded on the Montreal Stock Exchange and then the TSX Venture Exchange. It became a subsidiary of Anaconda Mining Inc. after Anaconda acquired the company in a stock swap deal in 2017.[5]
Property Description
Orex's Goldboro main property consisted of 37 contiguous claims (600 hectares) held under license from the Province of Nova Scotia. It is located along the eastern shore of Nova Scotia and is wholly owned by Orex. The property is situated 185 kilometers northeast of Halifax and is accessible by a 2.5 kilometer unpaved road from Highway 316 which links the village of Goldboro, Nova Scotia to the town of Antigonish, NS.[6] The main project location is found at Latitude: 45° 10´ North ; Longitude: 61° 40´ West (NTS 11F/04)
On November 26, 2009, following a joint venture agreement with Osisko Mining, Orex staked hundreds of additional contiguous claims which cover 960.8 square kilometers surrounding the Goldboro strike area. The current map of these claims highlighted in yellow is below. Initial exploration on these claims is now underway.
Resource Estimates
In September 2009, Orex published a Mineral Resource Estimate compliant with National Instrument 43-101 standards. They presented the resource estimate with a variety of cut off grades, the two most notable are represented below:[8]
With a cut-off grade of 0.5 g/t Au, the Mineral Resource was as follows:
The Measured, Indicated and Inferred Resource represents a total of 15,866,000 tonnes grading 2.21 g/t Au (1,085,600 ounces).
The Results of the 2009 Mineral Resource Estimate with a cut-off grade of 1.50 g/t Au are as follows:
The Measured, Indicated and Inferred Resource represents a total of 2,711,000 tonnes grading 4.56 g/t Au (803,100 ounces).
'''A major issue with this estimate was that 96 DD samples used in previous reserve estimates were assigned a value of 0 g/t in the model due to less than complete historic sampling required for the new geological model being used. This resulted in a significantly lower than expected resource. Orex is currently resampling the areas that these holes covered as well as new areas.'''
- 519,000 tonnes grading 3.08 g/t AU (51,400 ounces) within the Measured category
- 7,414,000 at 2.06 g/t Au (491,400 ounces) within the Indicated category; and
- 7,933,000 grading 2.13 g/t Au (542,800 ounces) within the Inferred category.
Joint venture with Osisko
On November 12, 2009, Orex signed an option and joint venture agreement with Osisko Mining.[9]
The key terms of the agreement are:
Between November 12, 2009 and September 29, 2015 Osisko is the manager of the project, with a joint management committee during the option period with two representatives from each party. This Management Committee will be responsible for revising programs submitted by Osisko and for approving and evaluating the results of all programs. Osisko has the tie casting vote.
On November 1, 2010 Orex reported that Osisko had incurred exploration and development expenditures in excess of the $1,500,000 minimum required by September 29, 2010. (The actual amount expended was reported as $3,120,000 in Osisko's November 11, MD&A) Osisko confirmed that it would continue to incur expenditures under the option and joint venture agreement. A drilling plan and budget for the next phase of the drilling campaign on the Goldboro Gold Property was to be prepared.[10] In Osisko's March 31, 2011 MD&A the company reported that the cumulative expenditures on the Goldboro property was $2,928,000.
On September 29, 2011, Osisko and Orex jointly announced that Osisko had allowed its option on the property to expire by not meeting the minimum expenditure requirements. Osisko stated "While the results from the 2010 and 2011 drilling campaigns are encouraging, they indicate the presence of a smaller deposit potentially minable by selective underground methods focussed on the veins, or alternatively a relatively shallow open pit operation, both of which are outside the scope of Osisko's exploration and acquisition strategy."
Current exploration activities (2009 to 2011)
Joint venture exploration activities
On January 27, 2010 Orex and Osisko began their first joint exploration.[12] A three-part campaign was planned with two drills. Osisko began with the 4,728 m / 18 holes Phase 2F drilling campaign, to some incomplete and/or non-compliant historic drill results with compliant data primarily in the deeper portions of the Ramp Area Mineral Resources and extending westward towards West Goldbrook. Following Phase 2F, Osisko continued with the Phases 2D (5,492 m / 28 holes) and 2E (2,769 m / 13 holes) drilling campaigns, which continued westward along the remaining 1.7 km segment of the Boston Richardson Deformation Zone from the Ramp through West Goldbrook to Dolliver Mountain.
As of April 29, 2010 59 holes for the Phases 2D, 2E and 2F drilling campaign, representing 12,989 metres, were completed. A 600m undrilled gap still exists between West Goldbrook and Doliver Mountain.[13]
During the same period Nova Scotia based Mercator Geological Services Limited and D.R. Duncan & Associates Ltd., were retained and completed a regional compilation-synthesis on the 960.8 km2 Goldboro Extension Property. A number of key Goldboro-type gold targets were identified and are currently being drill-tested using the Reverse Circulation ("RC") method to recover basal till and bedrock samples for gold assaying and whole-rock analysis.
Geological interpretation
The property is located within the Meguma Supergroup of the eastern Canada Appalachian Belt. The property is entirely underlain by sedimentary rocks of the Goldenville Group, which consist of altered greywacke, sandstone (arenite), and slate. The stratigraphic sedimentary succession of the Goldboro area is affected by the Upper Seal Harbour anticline. This anticline is an upright, ENE-trending tight fold with a 10° to 30° plunge to the east. In the apex of the anticline, the slate units are thicker than other sedimentary rock types. The following diagram illustrates the Goldenville & Upper Seal Harbor Anticlines and the relative location of gold mineralization being explored by Orex and Osisko:
The Goldboro mineralization has been previously referred to as a “saddle reef” lode-gold deposit type. In Nova Scotia, the Boston-Richardson mine (Upper Seal Harbour district) is a classic example of a “saddle reef” deposit. The gold mineralization at Goldboro occurs in association with and within a quartz vein swarm located in the hinges of regional anticlines, principally in black shale-argillite wall rocks. As such, Goldboro is not a classic “saddle reef” lode gold deposit type. The fine-grained folded sedimentary units have a constant thickness in the limb but not in the hinge of the fold, suggesting flexural-slip as the folding mechanism. Many key features within the gold deposits of the Upper Seal Harbour district show that the folding itself should be considered as the gold mineralizing process.
Gold mineralization at Goldboro occurs in quartz veins and disseminated sulphides in the wall rock. The mineralized wall rock mostly, but not exclusively, consists of shale-argillite (slate). Locally, the greywacke and arenite are cut by quartz veins and are mineralized. The veins are characterized by quartz, sulphide (auriferous arsenopyrite) and native gold (visible gold flakes have historically been observed in several slate belts). Wall rocks generally contain more sulphides than the veins, in the form of arsenopyrite selvedges.
History
A very detailed history of the mines and the works found on the property prior to 1915 can be found in a summary is presented below.
Boston Richardson Mine
In 1861 gold was discovered in quartz veins on the Isaac's Harbour anticline. In 1892, Howard Richardson was the first to note gold within shale and quartz veins which became generally known as the Boston Richardson Belt. Mining on the property began in 1892 when the Richardson Gold Mining Company started developing the belt.[25]
In 1896 the mine was operating at full capacity and by 1897 three shafts gave access to the ore at a depth of 60m. By 1900 the main shaft was 160 m deep and selective mining methods were being used and two Wilfley Concentrators were in operation. Two additional concentrators were installed in 1901. In 1902 another shaft was sunk which became known as the Boston Richardson Shaft, and which is still in existence to the present day.[8]
The Boston Richardson Mining Company took over the property in 1903 and resumed work on the Boston Richardson shaft which they extended to a depth of 122m which by 1905. A bromo-cyanide plant was built on the property in 1906 and gold recovery went up to 70%. The main shaft had reached a depth of 213m by 1902. Operations were stopped on August 15, 1908 because of financial difficulties.
Modern exploration
1980 to 1989
Very little additional work is documented about the property until 1981 when exploration by a series of junior exploration companies resumed.
In 1981 Pantino Mines Ltd. did some geophysical surveys and in 1984 a 529m diamond drill hole was drilled on the Boston Richardson Belt. In 1985 five diamond drill holes will drilled on the former West Gold Brook mine. Each hole intercepted many slate beds but few samples were taken.[41]
In 1987 Petromet Resources Ltd. and Greenstrike Gold corporation drilled an additional 5 diamond drill holes[41][42] and late in the year Omnitap Resources Inc. completed and additional 33 diamond drill holes. Helicopter borne magnetic and EM-16 surveys were also conducted.[43][44]
Past resource estimates
2006 resource estimate
In 2006 P&E Mining consultants was commissioned to produce a new NI43-101 compliant Resource estimate based on the results from the new 2005 drilling campaign.[61]
There was no new resource calculation for the entire strike length—only an update to the 225-m portion within the Ramp Area (which was newly drilled with large bore samples) was calculated. The reconciled resources outside the 225-m strike length of the Ramp Area for the remainder of the 1.5-km strike length was 800,800 ounces tabulated as follows:
2004 resource estimate
In 2004 Orex commissioned MRB & Associates to produce an NI43-101 compliant resource estimate based on past exploration activities and available data. The Technical report concluded that the resource defined at that point was 644,000 oz as summarized in the table below. This estimate did not apply any correction factors for the extreme nugget effect.[62]
1990 ore reserve calculation
External links
References
- Orex Exploration Company Snapshot retrieved 2010-08-05^
- Orex Exploration Company Snapshot retrieved 2010-08-05^
- Financial Times Business Profile: OX retrieved 2010-08-05^