Jump to content

Orex Exploration: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Yhzsailor (talk | contribs)
325 edits
No edit summary
Yhzsailor (talk | contribs)
325 edits
Line 104: Line 104:
'''The Measured and Indicated Resource represents a total of 2,711,000 tonnes grading 4.56 g/t Au (397,200 ounces).'''
'''The Measured and Indicated Resource represents a total of 2,711,000 tonnes grading 4.56 g/t Au (397,200 ounces).'''
===1990 Ore Reserve Calculation===
===1990 Ore Reserve Calculation===

In 1990 an Ore Reserve Calculation was commissioned. It determined between 1.4 and 2.4 million ounces of gold would be found on areas surrounding the former Boston Richardson shafts and the West Goldbrook mine:

* Ramp Area: 755,002 tonnes @ 1.19 to 2.42 g/t
* Main Ore Body: 19,500,000 tonnes @ 0.75 to 3.37 g/t
* West Goldbrook Area: 8,614,817 tonnes @ 0.53 to 0.84 g/t

This estimate explicitly excluded the East Goldbrook areas from these calculations and suggested that these areas could contain 10 million tons of ore with a grade of 2.8g/ton..<ref>{{Citation
| title = A re-appraisal of the Goldboro Property (Upper Seal Harbour district) Guysboroug County, Nova Scotia, Geology, metallurgy and ore reserves
| last = Roy
| first = Michel
| last2 = Labelle
| first2 = Jean-Pierre
| publisher = Orex Exploration
| place = Rouyn-Noranda
| origyear = 1990
| year = 1990
| month= August
| pages=12-14
| url = http://www.gov.ns.ca/natr/meb/data/ar/1990/AR_ME_1990-174.pdf
}}</ref>


===1989 Ore Reserve Calculation===
===1989 Ore Reserve Calculation===

Revision as of 01:45, 28 August 2010


Orex Exploration Inc.
Company typePublic
(TSX: OX)
IndustryMining
Founded1987
Headquarters
Montreal
,
Canada Canada
Key people
Mark Billings, President & CEO
Jacques Levesque, CFO
Julie Godard, Corporate Secretary
Michael A. Dehn, Director
David Hatchette, Director
Louis A.-Lapointe, Director
Claude Poulin, Director
ProductsGold
Revenue$0(2009)
Decrease$ million
Total assets$10.191 million(2009)[1]
Total equity$15.489 million (2009)[2]
Number of employees
1
Websitewww.orexexploration.ca

Orex Exploration is a Canadian advanced stage junior gold exploration company headquartered in Montreal, Quebec. It operates in Nova Scotia, Canada with a focus on exploring former gold mines and properties in the Goldboro, Nova Scotia, and surrounding areas of Guysborough County, Nova Scotia.[3]

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.

Property Description

Orex's Goldboro property consists 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.[4] The main project location is found at Latitude: 45º 10´ North ; Longitude: 61º 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:

Orex Mining Claims as of February 15, 2010[5]

Resource Estimates

Current 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:[6]

With a cut-off grade of 0.5 g/t Au, the Mineral Resource was as follows:

  • 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.

The Measured and Indicated 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:

  • 270,000 tonnes grading 4.99 g/t Au (43,300 ounces) within the Measured category
  • 2,441,000 tonnes at 5.99 g/t Au (353,900 ounces) within the Indicated category; and
  • 3,438,000 tonnes grading 3.67 g/t Au (405,900 ounces) within the Inferred category.

The Measured and Indicated Resource represents a total of 2,711,000 tonnes grading 4.56 g/t Au (397,200 ounces).

1990 Ore Reserve Calculation

In 1990 an Ore Reserve Calculation was commissioned. It determined between 1.4 and 2.4 million ounces of gold would be found on areas surrounding the former Boston Richardson shafts and the West Goldbrook mine:

  • Ramp Area: 755,002 tonnes @ 1.19 to 2.42 g/t
  • Main Ore Body: 19,500,000 tonnes @ 0.75 to 3.37 g/t
  • West Goldbrook Area: 8,614,817 tonnes @ 0.53 to 0.84 g/t

This estimate explicitly excluded the East Goldbrook areas from these calculations and suggested that these areas could contain 10 million tons of ore with a grade of 2.8g/ton..[7]

1989 Ore Reserve Calculation

An Ore Reserve calculation was produced by St-Michel Geoconseil in 1989 specific to the access portal ramp area. It concluded there was 1,068,547 metric tons of ore grading 6.2g/ton (un-cut) of gold for approximately 205,000 oz of gold in the area of the ramp.[8]

1988 Ore Reserve Calculation

In 1988 a non NI43-101 compliant Ore Reserve Calculation was compiled by Narex Ore Search Consultants and concluded there was 1,102,036 tons @ 0.194oz/ton indicated ore, for a total indication of 213,694oz of gold.[9]

Pre-1981

Reliable production figures are only available for the Boston Richardson belt. From 1893 to 1912 mine production was recorded as 414 887 short tons grading 0.132 Oz/T (376 383 tonnes grading 4.53 g/t Au) for a total production of 54 871 ounces of gold. The head grade was estimated to be considerably higher at 6.8 g/t Au but poor technology at the time resulted in the lower recovered grade.[10] Anecdotal reports from the descendants of former miners indicate that a certain amount of loss due to theft occurred. This is possible due to the nugget nature of the gold found in the belts. It has been said that a lot more gold was taken out of the belts than was officially reported. Some claim that some mining families never worked for many decades following the closure of the mines yet always had money to spend.

Joint Venture with Osisko

On November 12, 2009, Orex signed an Option and Joint Venture agreement with Osisko Mining.[11]

The key terms of the agreement are:

  • Osisko invested $1.3million in Orex and received 13,000,000 shares at a price of $0.10/share
  • Osisko received 13,000,000 transferable warrants to acquire one common share at a price of $.125/share over a period of 3 years
  • Osisko receives a 50% interest in the property before September 29, 2013 if it incurs exploration/development expenditures of:
    • $1,500,000 before September 29, 2010
    • $3.5 million (aggregate) on or before September 29, 2011
    • $8.0 million (aggregate) on or before September 29, 2013
  • Osisko may receive a 60% interest in the property if it completes a prefeasibility study before September 29, 2015

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.

Current Exploration Activities

On January 27th, 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 all 59 holes for the Phases 2D, 2E and 2F drilling campaign, representing 12,989 metres, were completed. [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. To date 194 RC drill holes are completed for 1,513 meters and 758 samples taken.[14]

History

A very detailed history of the mines and the works found on the property prior to 1915 can be found in Naert, Karl A. (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, March, 1988 (PDF), Scarborough: Narex Ore Search Consultants Inc., pp. 24–35 {{citation}}: Unknown parameter |month= ignored (help) 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.[15]

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 the main shaft was 160m 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.[16]

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 15th, 1908 because of financial difficulties. In 1909 the New England Mining Company took over operations until 1912. [17]

In 1926 the Metals Mining and Smelting Corporation of Canada acquired the property and attempted to recover gold from the old mine tailings.[18]


Goldboro, NS. A train is seen coaling on the wharf near a waiting schooner.[19]
Richardson Gold Mine, NS[20]
Surface plant of the Boston Richardson Mining Co., Upper Seal Harbour[21]
Horizontal Projection of Survey Down East Shaft Made After Cave In of the Richardson Mine[22]
Boston-Richardson Mine-Vertical Shaft and Vertical Projection of Incline Shaft Showing Depth Reached and Distance Driven South Side[23]
Cross-Sections of the Boston-Richardson Mine[24]
Cross-Sections of the North and South Side of the Boston-Richardson Mine[25]
Plan Projections and Transverse Section of Underground Workings of Boston-Richardson Mine[26]
New England Mining Company Stock Certificate[27]

Dolliver Mountain Mine

An underground mine was active on Dolliver Mountain between 1901 and 1905. Dolliver mountain is located to the west of the Boston Richardson Shaft. In 1902 the shaft had a depth of 58m and intersected three ore belts on of which (the "Partington Belt") was 10m in width. In 1903 the shaft reached a depth of 81m and intersected the "Forge Belt" which was 7m in width. By 1904 the shaft was 149m deep and in 1905 a 152m drill hole was drilled from the bottom of the shaft which intersected several more bodies of quartz and slate. The mine has remained idle since 1905.[28]

View of stamp mill and portion of ore tramway.[29]
File:NSARMQE185A220E.jpg
Surface plant of Dolliver Mountain Gold Mining Co., Upper Seal Harbour[30]
Dolliver Mountain Mine, Upper Isaacs Harbour Gold District, Guysborough,Nova Scotia County[31]

West Goldbrook Mine

The West Gold Brook mine is located west of the Boston Richardson Shaft. Between 1909 and 1910 five ore belts were discovered in the West Gold Brook Mine. Milling tests on the ore from three of the belts was not satisfactory and the mine was abandoned. Locarno Copper Mines Ltd. Sank a new shaft west of the original one between 1929 and 1931. In 1931 a metallurgical test recovered 1.61 ounces of gold from 1.1 Short tons of ore. In 1956 The Canso Mining Corporation dewatered the Locarno shaft and did some basic exploration but work was stopped due to financial difficulty.[32]

East Goldbrook Mine

In 1907 a shaft was sunk \to the east of the Boston Richardson shaft. In 1908 three ore belts were discovered and some rich ore was discovered in one, but no further work is noted. The East Goldbrook shaft was dewatered between 1931 and 1934 by Renada Mines Ltd. who sampled the workings and assaying gave results between 1.61 to 4.26 g/t Au.[33]

East Goldbrook Mine Plan 150' Level[34]

Modern Exploration

1980 to 1989

Very little additional work is documented about the property until 1981 when exploration by 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.[35]

In 1987 Petromet Resources Ltd. and Greenstrike Gold corporation drilled an additional 5 diamond drill holes[36] [37] 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.[38][39] The goal of this campaign was to establish the depth and breadth of the Boston Richardson Belt. It was also targeted at the East Goldbrook property and on targets under the Boston Richardson Belt. It lead to the detection of four additional belts under the Boston Richardson Belt and additional belts over the Boston Richardson Belt in the East Goldbrook area. These belts showed impressive gold values and visible gold was found in almost every hole.

The option on the property was conveyed to Orex Exploration in 1988.

In 1988 a surface and underground exploration program was undertaken to cover the property to the west of the Boston Richardson Mine.[40][41] Course gold was found in quartz veins and free gold was found in graphite black shale and fourteen belts of gold bearing ore had been identified. During 1988 the Boston Richardson Mine shaft was rehabilitated to facilitate an underground exploration program.[42][43] Orex Exploration sought ACOA funding to develop a new modern mine.[44] and sought Tenders for conducting a Pre-Feasibility and Feasibility Study.[45]In addition an access decline (often called "The Ramp" and "Ramp Area") was developed to validate the drilling results and muck sampling was undertaken.

At the beginning of 1989 the company conducted a metallurgical test on muck samples from 1988 and found that the results were much higher than those determined using atomic absorption sampling on core samples from the same areas. A milling test on several new diamond drill holes was conducted.

In 1989 the company also completed a Pre-Feasibility and two feasibility Studies.

The Pre-Feasibility study recommended underground mining, a standard gravity/floatation mill and concluded that a profit of $40 per ton would be realized. [46]

The first feasibility study expanded on the pre-feasibility study and described three possible options, two of which involved variations on a portable 500 metric ton/day mill and underground mining, and the third option involved open pit mining, selective underground mining and a 5,000 metric ton/day mill. All scenarios were considered economically viable but the third option of an open pit mine and large mill was considered to have the largest possible return to shareholders and was the recommended option.[47]

The second feasibility study was produced two months after the first and recommended only a modified sub-level retreat mining methodology with no mention of the open pit mining option described in the first feasibility study. It concluded that this was economical within the capital available to the company.[48]

The company then notified the Department of the Environment for the Province of Nova Scotia of its intent to proceed with a Gold Mining Project.[49] The company proposed to undertake open pit mining and recover the gold using a gravitational mill with flotation process and cyanide processing. A public meeting was held as part of this process on March 27, 1989 with the major concerns being the environmental control requirements from the government, possible stream contamination and site reclamation.[50]

The company also produced an Economic Evaluation of the project in 1989 which estimated an average 195 direct jobs and 293 indirect jobs would be created per year in the first 4 years and 240 direct jobs in subsequent years. The evaluation stated that direct economic benefits of $13 million could be expected in the first four years in the Guysborough County area. In addition, it forecast expenditures of $70 million in initial capital investment for equipment and machinery and subsequent expenditures of $12.8 million per year - much of which was to be sourced in the Guysborough and Antigonish Counties. The total value of the project to the community was forecast to be $123.25 million in the first four years of operation.[51]

Between 1989 and 1990 additional underground definition drilling was undertaken and two underground bulk samples of 7 metric tons were mined out.

1990 to 2004

Between 1990 and 1993 very little exploration work occurred on the property while a scientific debate raged about the correct way to accurate measure the gold deposit's grade and numerous technical reports and assessments were completed.

In 1990 the terms of reference for an environmental assessment were produced and the environment assessment was conducted.

The main controversy was whether the deposit was a high grade deposit (due to the presence of large numbers of gold nuggets) or low grade deposit (due to the fine gold found in the slate belts). Conventional fire assays were yielding significantly lower grade results than metallurgical tests which were consistently returning high grade results. Continous Grind Leach techniques were evaluated under option with Minnova Inc., but did not yield satisfactory results. In 1992 a Vat Leach test was conducted with Novagold (under option) which yielded grades of 4-6g/t Au with an 84% recovery rate. NovaGold was forced to drop its option due to financial difficulties.

In 1993 Orex drilled six more diamond drill holes to evaluate the extent of the high grade resource. The results were analyzed by CRM labs and were just as problematic, returning the same results as found by Minnova, but with large amounts of gold being found unrecovered by the sampling protocol. This was due to the high nugget effect and the failure of the large gold nuggets to dissolve in the cyanide concentrations.

Placer Dome contacted Orex in 1995 and offered to assist as they had encountered similar sampling problems in the past. Placer sampled the stock pile of ore recovered in 1988-89 in a very methodical way. They took samples of four types of rock: Greywacke, Slate, Quartz Vein and Vein. They discarded any samples with visible gold. The results were extremely encouraging showing 1g/t in Greywacke, 2.82g/t in Slate, 16.15 g/t in Quartz Vein and 36.37 g/t in veins.[52]

In 1995 Placer Dome offered $30 million to acquire a 65% interest in the Goldboro property. Placer Dome proceeded to obtain environmental releases from the Province of Nova Scotia for past mining environmental problems (related to the turn of the century activities) delays in obtaining this release meant exploration did not start again until late in 1995. Due to budget cutbacks, conventional sampling was reinstated with a return to the previous "low grade" results. In 1996 Placer dome dropped its option in order to focus on international properties and other ventures.[53]

The site was essentially abandoned between 1996 and 2004. The shaft house and mechanical buildings were significantly vandalized, and all of the core samples were largely lost.

2004 to 2009

In February 2004, MRB & Associates was retained by Orex to prepare an independent technical report on the Goldboro property. The report was a joint effort between a team of independent consultants (InnovExplo Inc., A.S. Horvath Consulting, Tech2Mine Inc., and MRB & Associates), supervised by Jean Lafleur, M.Sc. (Senior Technical Advisor to Orex).

One of the reasons for this independent study was to review the geology of the Goldboro property and Meguma district in Nova Scotia, and compare the characteristics of Meguma-style deposits to those of the Bendigo and Ballarat deposits in the Lachlan fold belt of Central Victoria, Australia. Another purpose was to review historical sampling and analytical grade determination procedures at Goldboro and provide an assessment of the data quality and suitability of these historical results as they pertain to:

  • mineralization characteristics and recommendations for future sampling, grade determination, and QA/QC protocols;
  • data quality and integrity for use in resource/reserve estimation, and;
  • comparison of the sampling, analytical determination and reserve estimation methods with those used at deposits in the Bendigo-Ballarat district.

The conclusions and recommendations stemming from the study set the stage for the 2005 exploration program undertaken by Orex, specifically the conclusions regarding grade determinations. Horvath made the following conclusions (among others):

  • Historical conventional sampling, processing and analytical gold determination protocols consistently under-estimated the grade due to the extreme nugget effect;
  • The only reliable method of obtaining accurate and precise grade determinations for Goldboro mineralized samples is by metallurgical testing/processing of adequately sized representative samples.

Orex began an exploration program in February 2005. Twenty-three (23) diamond drill holes of HQ diameter core were completed for a total of 2,355 metres (BR05-001 to BR05-023). Drilling was concentrated in a 225-metre wide area, centred on Section 8675E of the Boston Richardson belt. The individual sample weight was estimated to be 7.75 kg per metre of recovered core.

The purpose of the drill program was to test a small area of known shallow mineralized zones by drilling fences of holes on a spacing of no greater than 25 metres between sections. The proposed pattern of drilling and number of holes was designed to allow two (2) separate shallow areas to be similarly tested. Four (4) holes were twinned to previous holes for comparative analysis. Recognized mineralized zones were assayed using conventional fire assay with an atomic absorption or gravimetric finish, and at the end of the program, sample composites (made by combining reject samples from multiple drill holes previously analyzed by conventional fire assay) were made and sent to Lakefield Research for metallurgical testing. A resource estimate in compliance with CIM Definitions and Standards on Mineral Resources and Mineral Reserves was undertaken at the end of the program by P & E Mining Consultants Inc. using the metallurgical sample results (Armstrong, Puritch and Horvath, 2006).

Orex began an exploration program in February 2008 that consisted of a diamond drill program comprising 12,201.5 metres in forty-five (45) holes (also refer to Section 11 (Item 13) of this report). The average drill hole length was 250 metres. Drilling was concentrated between West Goldbrook and East Goldbrook on Crown Land surface rights. The purpose of the drill program was to infill the previous drill programs and test the extensions of gold mineralization to the east and west of the Boston-Richardson zone.

In September 2009, Orex commissioned a Mineral Resource Estimate which was compliant with National Instrument 43-101.

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 f 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 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 dxclusively, 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.

Faribault

In 1885, E.R. Faribault mapped Nova Scotia's gold fields for the Geological Survey Department (Government of Canada). He focused on the intricate folds in the gold-bearing formations along the southeast coast of Nova Scotia known as the Meguma Group. He recognized that the gold occurred like saddles along the crests of small anticlines and he discovered many large and small ore bodies. His discoveries were critical to the present knowledge of the location of gold in Nova Scotia.[54]

In 1893, Map #27 by the Geological Survey Department was produced by E.R. Faribault to illustrate a report commissioned by the Department from Hugh Fletcher and E.R. Faribault in 1886. This map (below) illustrates the extensive known gold fields in the areas around Goldboro. Many of these properties are currently claimed by Orex Exploration, while some others are held by other mineral claim holders. In addition detailed cross sections of the Isaac's Harbour gold district and also of the Boston Richardson mine were produced by Faribault (below).

Province of Nova Scotia, Guysborough County, Isaacs Harbour, Sheet No 27[55]
Plan and Sections, Isaacs Harbour Gold District, Guysborough County, Nova Scotia [56]
Plan and Sections, Upper Seal Harbour, Guysborough County, Nova Scotia [57]

Nugget Effect

A major hurdle for Orex has been to evaluate the gold content of the mineralized belts. The gold distribution is subject to a severe “nugget effect” with a strong segregation component. In the case of Goldboro, gold appears as large nuggets, fine disseminations within or bordering arsenopyrite crystals and fine gold grains associated with carbonaceous material. This particular distribution of gold grains may explain the fact that regular assaying methods (A.A.; F.A; metallics) yield lower gold values than a metallurgical balance from mill-tests.

Historically, the severe “nugget effect” produced by the extreme variability in gold size and distribution within the Goldboro mineralized belts forced companies to implement a number of sampling and grade determination programs. The nugget effect is so extreme that collecting and processing samples of a size adequate enough to overcome the nugget effect is problematic using conventional analytical methods. The programs have resulted in a wide variety of sample types tested by several different processing protocols on the initial and sub-split sample sizes. Sample types have included:

  • surface and underground grab samples,
  • surface and underground drill core samples,
  • drill sludge samples,
  • drill core composite samples,
  • underground chip samples,
  • underground muck samples, and
  • underground bulk samples.

The results from these tests clearly demonstrate that undersized initial samples and/or improper sub-split sizes for the crush and/or grind sizes could produce imprecise determinations of grade.

Bendigo Ballarat

Many comparisons have been made between the gold deposits of the Goldfields area of Central Victoria (Australia) and the Meguma deposits of Nova Scotia (Canada). The comparisons show that these deposits share numerous similarities but also display some differences. [58]

The comparisons between deposits in the Goldfields area of Australia and Meguma deposits in Nova Scotia could have a significant impact for gold exploration at Goldboro and elsewhere in the Meguma Terrane. The Victoria examples demonstrate that narrow quartzvein gold deposits, similar to those in Meguma, can be mined profitably. Furthermore, it also demonstrates that disseminated, low-grade concentrations of gold (1-2 g/t Au) can be mined as economically viable deposits.

This comparison indicates that a potential for larger deposits exists in Nova Scotia (the extension of the Meguma deposits at depth is virtually untested). The Goldfields area in Australia hosts the Bendigo and Ballarat giant sedimentary-hosted lode-gold deposits. At Bendigo, 22 Moz of gold have been produced since 1851, and ~12 Moz of gold has been produced at Ballarat since 1850. Bendigo and Ballarat may turn out to be unique, but the features of the Australian mineral deposit model that are missing at Goldboro should nonetheless be tested by an exploration program. Finally, exploration programs in Australia tell us that the grade of mineralized veins cannot be assessed without bulk sampling, and where applicable, declines must be an integral part of the exploration strategy.

High Grade/Low Grade

Two different approaches to geological modeling can be used for resource estimation at Goldboro: the mineralized zones can be interpreted as either: (i) narrower and higher grade folded belts (about sixteen (16) belts); or (ii) they can be grouped into larger structural domains (about four (4) domains). For the 2009 Mineral Resource Estimate, InnovExplo opted for the first approach (e.g., individual belts rather than domains). In both approaches, the higher grade material is in similar locations—fold hinges where maximum dilation seems to have occurred—although differences can occur in the distribution of lower grade material. Some tests have been completed using the two different approaches, and both models gave similar totals for contained ounces.

References

  1. ^ "Orex Exploration Company Snapshot". Retrieved 2010-08-05. {{cite web}}: Text "1404" ignored (help); Text "2194" ignored (help); Text "fpsn" ignored (help); Text "fpsn" ignored (help)
  2. ^ "Orex Exploration Company Snapshot". Retrieved 2010-08-05. {{cite web}}: Text "1404" ignored (help); Text "2194" ignored (help); Text "fpsn" ignored (help); Text "fpsn" ignored (help)
  3. ^ "Financial Times Business Profile: OX". Retrieved 2010-08-05.
  4. ^ Bourgoin, Mark (2004). Technical Report Goldboro Property (PDF). Val D'Or: MRB & Associates Mining Consultants. p. 4. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
  5. ^ Province of Nova Scotia. "Orex Mining Claims as of February 15, 2010". Province of Nova Scotia. Retrieved 22 August 2010.
  6. ^ Gervais, Donald; Carrier, Alain; Brousseau, Karine (2009) [2009], TECHNICAL REPORT ON THE 2009 MINERAL RESOURCE ESTIMATE FOR THE GOLDBORO PROPERTY (PDF), Val-d’Or: InnovExplo, pp. 6–7 {{citation}}: Cite has empty unknown parameter: |chapterurl= (help); Unknown parameter |month= ignored (help)
  7. ^ Roy, Michel; Labelle, Jean-Pierre (1990) [1990], A re-appraisal of the Goldboro Property (Upper Seal Harbour district) Guysboroug County, Nova Scotia, Geology, metallurgy and ore reserves (PDF), Rouyn-Noranda: Orex Exploration, pp. 12–14 {{citation}}: Unknown parameter |month= ignored (help)
  8. ^ Parent, Guy (1989) [1989], Ore Reserves Calculation, Ramp Area, Goldboro Property (PDF), Rouyn-Noranda: St-Michel Geoconseil, p. 14 {{citation}}: Unknown parameter |month= ignored (help)
  9. ^ Naert, Karl A. (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, March, 1988 (PDF), Scarborough: Narex Ore Search Consultants Inc., p. 17 {{citation}}: Unknown parameter |month= ignored (help)
  10. ^ Nova Scotia Mines Bureau Mines 1928 Annual Report. Government of Nova Scotia. 1928. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  11. ^ "Orex and Osisko Sign Option and Joint Venture Agreement" (Press release). OREX EXPLORATION INC. November 12, 2009. Retrieved August 16, 2010.
  12. ^ "Orex Exploration Inc.: 2010 Drilling Campaign Starts at Goldboro Gold Project, Nova Scotia" (Press release). Orex Exploration. January 27, 2010. Retrieved August 6, 2010.
  13. ^ "Orex And Joint Venture Partner Osisko Complete Phase 2 Delineation Diamond Drilling at Goldboro" (Press release). Orex Exploration. April 29, 2010. Retrieved August 6, 2010.
  14. ^ "Orex Exploration Announces More Drill Results at Goldboro; Advances Regional Exploration Program" (Press release). Orex Exploration. June 10, 2010. Retrieved August 6, 2010.
  15. ^ Bourgoin, Mark (2004). Technical Report Goldboro Property (PDF). Val D'Or: MRB & Associates Mining Consultants. pp. 11–12. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
  16. ^ Gervais, Donald; Carrier, Alain; Brousseau, Karine (2009) [2009], TECHNICAL REPORT ON THE 2009 MINERAL RESOURCE ESTIMATE FOR THE GOLDBORO PROPERTY (PDF), Val-d’Or: InnovExplo, pp. 6–7 {{citation}}: Cite has empty unknown parameter: |chapterurl= (help); Unknown parameter |month= ignored (help)
  17. ^ Gervais, Donald; Carrier, Alain; Brousseau, Karine (2009) [2009], TECHNICAL REPORT ON THE 2009 MINERAL RESOURCE ESTIMATE FOR THE GOLDBORO PROPERTY (PDF), Val-d’Or: InnovExplo, pp. 6–7 {{citation}}: Cite has empty unknown parameter: |chapterurl= (help); Unknown parameter |month= ignored (help)
  18. ^ Naert, Karl A. (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, March, 1988 (PDF), Scarborough: Narex Ore Search Consultants Inc., p. 5 {{citation}}: Unknown parameter |month= ignored (help)
  19. ^ "Boston Richardson's Gold Co. wharf". NSARM Public Archives of Canada Collection: PA no. 20759. Retrieved 6 August 2010.
  20. ^ B.T.A. Bell (1896). "Richardson Gold Mine, NS". The Canadian Mining, Iron and Steel Manual (1896). NSARM Library: TN B41 1896. Retrieved 6 August 2010.
  21. ^ Wyatt Malcom (1912). "Surface plant of the Boston Richardson Mining Co., Upper Seal Harbour". Gold Fields of Nova Scotia. NSARM Library: QE185 A2 no.20-E (mfm 3715). Retrieved 6 August 2010.
  22. ^ "Horizontal Projection of Survey Down East Shaft Made After Cave In of the Richardson Mine". Retrieved 6 August 2010.
  23. ^ "Boston-Richardson Mine-Vertical Shaft and Vertical Projection of Incline Shaft Showing Depth Reached and Distance Driven South Side". 1907. Retrieved 6 August 2010.
  24. ^ "Cross-Sections of the Boston-Richardson Mine". 1907. Retrieved 6 August 2010.
  25. ^ "Cross-Sections of the North and South Side of the Boston-Richardson Mine". 1909. Retrieved 6 August 2010.
  26. ^ "Plan Projections and Transverse Section of Underground Workings of Boston-Richardson Mine". 1926. Retrieved 6 August 2010.
  27. ^ "New England Mining Company Stock Certificate". 1926. Retrieved 6 August 2010.
  28. ^ Bourgoin, Mark (2004). Technical Report Goldboro Property (PDF). Val D'Or: MRB & Associates Mining Consultants. pp. 11–12. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
  29. ^ E.R. Faribault. "View of stamp mill and portion of ore tramway". NSARM Public Archives of Canada Collection (Geological Survey of Canada): PA no. 51442. Retrieved 6 August 2010.
  30. ^ Wyatt Malcolm (1911). "Surface plant of Dolliver Mountain Gold Mining Co., Upper Seal Harbour". Gold Fields of Nova Scotia. Dept. of Mines, Canada, NSARM Library: QE185 A2 no.20-E (mfm 3715. Retrieved 6 August 2010.
  31. ^ E.R. Faribault (1904). "Dolliver Mountain Mine, Upper Isaacs Harbour Gold District, Guysborough County, Nova Scotia". Gold Fields of Nova Scotia. Geological Survey of Canada, Multicoloured Geological Map 850. Retrieved 6 August 2010.
  32. ^ Bourgoin, Mark (2004). Technical Report Goldboro Property (PDF). Val D'Or: MRB & Associates Mining Consultants. pp. 11–12. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
  33. ^ Bourgoin, Mark (2004). Technical Report Goldboro Property (PDF). Val D'Or: MRB & Associates Mining Consultants. pp. 11–12. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |month= ignored (help)
  34. ^ "East Goldbrook Mine Plan 150' Level". Retrieved 6 August 2010.
  35. ^ Naert, Karl A. (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, March, 1988 (PDF), Toronto: Narex Ore Consultants, p. 8 {{citation}}: Unknown parameter |month= ignored (help)
  36. ^ Naert, Karl A. (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, March, 1988 (PDF), Toronto: Narex Ore Consultants, p. 8 {{citation}}: Unknown parameter |month= ignored (help)
  37. ^ Bottrill, Terrance J. (1987) [1987], Report on the Winter 1987 Exploration Program .... Upper Seal Harbour Gold District and Boston - Richardson Mine .... Volume 2 - Logs and Drawings (PDF), Toronto: MPH Consulting Ltd. {{citation}}: Unknown parameter |month= ignored (help)
  38. ^ Report on Diamond Drill Program - 1989 By Onitap Resources Inc. Exploration License No. 14397-Ref 11F4D Goldboro Area - Guysborough County, Nova Scotia (PDF), Scarborough, Ontario: Onitap Resources, 1989 [1989] {{citation}}: Unknown parameter |month= ignored (help)
  39. ^ Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldborough Area, Guysborough County, Nova Scotia (PDF), Scarborough, Ontario: Onitap Resources, 1987 [1987] {{citation}}: Unknown parameter |month= ignored (help)
  40. ^ Naert, Karl (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, November 1988 (PDF), Scarborough, ON: Narex Ore Search Consultants {{citation}}: Unknown parameter |month= ignored (help)
  41. ^ Naert, Karl A. (1988) [1988], Review of the Exploration Program Performed by Onitap Resources Inc. in the Goldboro Area .... Development License No. 0114, March, 1988 (PDF), Scarborough: Narex Ore Search Consultants Inc. {{citation}}: Unknown parameter |month= ignored (help)
  42. ^ Gagnon, Jean; Lampron, Sylvie; St-Michel, Andre (1988) [1988], Underground Exploration Program at the Goldboro Property (PDF), Rouyn-Noranda: St-Michel Geoconseil {{citation}}: Unknown parameter |month= ignored (help)
  43. ^ Gagnon, Jean; Dube, Martin; St-Michel, Andre (1988) [1988], Additional Information for the Underground Exploration Program at the Goldboro Property (PDF), Rouyn-Noranda: St-Michel Geoconseil {{citation}}: Unknown parameter |month= ignored (help)
  44. ^ Production Feasibility Study, Request for Financial Support, Atlantic Canada Opportunities Agency (PDF), Goldboro, NS: Orex Exploration, 1988 [1988] {{citation}}: Unknown parameter |month= ignored (help)
  45. ^ Legault, Laurier (1988) [1988], Response to the Invitation to Tender on the Feasibility Study for Goldboro Project (PDF), Val d'Or: Legault, Fournier, Gauthier & associes inc. {{citation}}: Unknown parameter |month= ignored (help)
  46. ^ Rousseau, Gilbert (1989) [1989], Goldboro Project Pre-Feasibility Study (PDF), Val d'Or: St-Michel Geoconseil {{citation}}: Unknown parameter |month= ignored (help)
  47. ^ St-Michel, Andre; Jean, Johanne (1989) [1989], Goldboro Project Feasibility Study (PDF), Val d'Or: St-Michel Geoconseil {{citation}}: Unknown parameter |month= ignored (help)
  48. ^ Rousseau, Gilbert (1989) [1989], Goldboro Project Feasibility Study (PDF), Rouyn-Noranda: St-Michel Geoconseil {{citation}}: Unknown parameter |month= ignored (help)
  49. ^ Registration of the Goldboro Project with the Nova Scotia Department of Environment (PDF), Rouyn-Noranda: Orex Exploration Inc., 1989 [1989] {{citation}}: Unknown parameter |month= ignored (help)
  50. ^ Notice of a Project, Goldboro Project (PDF), Rouyn-Noranda: Orex Exploration Inc., 1989 [1989], pp. 2, 11–12, {{citation}}: Unknown parameter |month= ignored (help)CS1 maint: extra punctuation (link)
  51. ^ Registration of the Goldboro Project with the Nova Scotia Department of Environment (PDF), Rouyn-Noranda: Orex Exploration Inc., 1989 [1989], pp. 18–22 {{citation}}: Unknown parameter |month= ignored (help)
  52. ^ Assessment Report On 1995 Diamond Drill Programme Exploration License 000502 Goldboro Nova Scotia Volume 1 (PDF), Val-d’Or: Placer Dome Canada, 1996 [1996]
  53. ^ Gervais, Donald; Carrier, Alain; Brousseau, Karine (2009) [2009], TECHNICAL REPORT ON THE 2009 MINERAL RESOURCE ESTIMATE FOR THE GOLDBORO PROPERTY (PDF), Val-d’Or: InnovExplo, pp. 6–7 {{citation}}: Cite has empty unknown parameter: |chapterurl= (help); Unknown parameter |month= ignored (help)
  54. ^ Nova Scotia Museum. "E. R. Faribault (1855-1934)". Museum of Nova Scotia. Retrieved 21 August 2010.
  55. ^ Faribault, E.R. (1893). "Province of Nova Scotia, Guysborough County, Isaacs Harbour, Sheet No 27". Government of Canada. Retrieved 21 August 2010. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  56. ^ Faribault, E.R. (1904). "Plan and Sections, Isaacs Harbour Gold District, Guysborough County, Nova Scotia". Government of Canada. Retrieved 21 August 2010. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  57. ^ Faribault, E.R. (1899). "Plan and Sections, Upper Seal Harbour, Guysborough County, Nova Scotia". Government of Canada. Retrieved 21 August 2010. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  58. ^ Ryan, R.J.; Ramsay, W.R.H. (1996), "The Victoria Goldfields of Australia: Meguma south?", in Ed (ed.), Minerals and Energy Branch, Twentieth Annual Review of Activities, Nova Scotia Department of Natural Resources, Minerals and Energy Branch Information Series ME 24. {{citation}}: |editor-first= missing |editor-last= (help); Missing or empty |title= (help); line feed character in |publisher= at position 72 (help)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Orex_Exploration&oldid=381420709"