Emgold Mining Corporation is advancing the exploration and re-development of the former Idaho-Maryland Mine located in Grass Valley, California, to return the famous gold mine to production. The Idaho-Maryland Mine was discovered in 1851, produced from 1862 through 1956 and is the second largest historical producer in California. Total recorded production was 2,383,000 ounces of gold from 5,546,000 short tons for a recovered grade of 0.43 ounces of gold per short ton.
The Idaho-Maryland is located in the Grass Valley Mining District which bears structural and historic gold production similarities to the prolific Red Lake District of Ontario, Canada. Both districts host large, high-grade gold deposits dominating district production and important high-grade targets which are blind and do not outcrop, requiring exploration and development from underground locations. Grass Valley District gold production (1851-1956) was over 13 million ounces from 25 million tons with a recovered grade of 0.52 opt, compared with Red Lake District production (1930s - present) of 18 million ounces from 27.7 million tons at 0.65 opt. The gold deposits of Grass Valley and Red Lake are strikingly similar on a district-scale and the importance of the geologic features in identifying major gold deposits is only now being recognized by the gold mining industry.
The three largest, bonanza-grade greenstone-hosted oreshoots known are the historic Idaho-Maryland's No. 1 Vein oreshoot in the Grass Valley District, the Main Shoot in the High Grade Zone of the Red Lake District, Ontario, Canada and the Oroya Oreshoot at the Golden Mile, Kalgoorlie, Australia. These contained 1 million, 1.5 million, and 3 million ounces gold respectively, from continuous bodies exceeding 1 opt in grade. Emgold has identified 26 large exploration targets at the Idaho-Maryland that have similar potential to these oreshoots and is therefore planning systematic underground exploration of these targets.
The City of Grass Valley is located on the western slopes of the Sierra Nevada and is within driving distance to Sacramento, Reno and Lake Tahoe. The City of Grass Valley has a population of approximately 12,000 people and Nevada County has a population of approximately 92,000.
The Idaho-Maryland property comprises approximately 2,800 acres of mineral land, with 37 acres of surface rights centered around the New Brunswick shaft, and 101 acres of surface rights south and west of the Idaho Shaft. The minerals rights are defined as sub parcels in a Quit Claim Deed.
The mineral rights are restricted to a variable depth from surface and in general, are contiguous below 200 feet from surface. Emgold has an agreement with the mineral rights holders that include a mining lease and option to purchase the property. The term of the lease agreement is five years commencing on June 1, 2002. During the term of the lease agreement, any production from the property will be subject to a 3% Net Smelter Royalty (NSR).
The Idaho-Maryland project is a structurally controlled, mesothermal gold deposit located in the northern portion of the Sierra Nevada Foothills Gold Belt. This region produced approximately 17 million ounces of gold until all of the gold mines in the district closed in 1956 due to the low gold price of $35 per ounce.
Two Technical Reports as defined in National Instrument 43-101 were prepared by AMEC E&C Services Ltd. The latest (November 2004) Technical Report presents a base resource using the historic Idaho-Maryland Call Factor (MCF) of 1.44 consisting of Measured and Indicated Mineral Resource of 1.666 million tons at 0.28 ounces per ton (opt) gold containing 472,000 ounces of gold and Inferred Mineral Resources of 2.526 million tons grading 0.38 opt gold containing an additional 952,000 ounces of gold.
- Idaho-Maryland Project Development Activities and Strategies
- Identified 26 gold exploration targets in seven large groups distinguished by dominant structure controlled mineralization
- Received surface drilling permits at four different locations
- Completed a surface gold exploration program consisting of over 21,300 ft of diamond drilling in thirty-one holes
- Completed a geotechnical and ceramics feedstock test program consisting of over 3,500 ft of diamond drilling in seven holes
- Completed a NI43-101 Preliminary Assessment Report based on results of the surface exploration program
- Applied for a Conditional Mine Use Permit for underground exploration and development, and construction and operation of gold and ceramics production facilities (production facilities are contingent on positive feasibility studies)
- Assist with the Lead Agency Environmental Impact Report for the Idaho-Maryland Mine required for the Use Permit
- Design and operate a Ceramext Demonstration Plant to produce high quality ceramic building products
- Upon receipt of the Mine Use Permit, design and install a decline to 750 ft level or possibly lower
- Process all development rock using the Ceramext™ technology
- Complete pre-feasibility and feasibility studies to make a ceramics production decision
- Construct and operate surface infrastructure and ceramics manufacturing facilities should a positive feasibility study be completed
- Conduct underground gold exploration between 200 ft and 750 ft levels
- Conduct pre-feasibility and feasibility studies to make a gold production decision
- Construct and operate gold production facilities should a positive feasibility study be completed
- Develop surface infrastructure and milling facilities
- Start production
Back to Top
REGIONAL GEOLOGY
The Idaho-Maryland Mine and the Grass Valley Mining District are situated in the northern portion of the Sierra Nevada Foothills Gold Belt. This belt averages 50 miles in width, and extends for 320 miles in a north-northwest orientation along the western slope of the Sierra Nevada range.
The extent of the Sierra Nevada Foothills Gold Belt coincides closely with the outcrop area of the Sierra Nevada Foothills Metamorphic Belt.
The Sierra Nevada Foothills Metamorphic Belt comprises a complex collage of lithologic units formed as a result of northward lithospheric plate subduction and transpression at a collisional plate boundary during the late Jurassic to early Cretaceous Nevadan Orogeny. The basement rocks of the belt are submarine meta-volcanics, meta-sediments, and oceanic crustal rocks of Ordovician to Jurassic age.
The north-northwest structural grain is defined by a series of subparallel, right-lateral wrench faults that represent deep-seated suture zones.
These structural breaks separate individual accreted terranes. Discontinuous belts of alpine type ultramafic intrusions (serpentinites), and a serpentinite-matrix tectonic mélange containing deformed slabs of Jurassic ophiolitic, volcanic, and sedimentary rocks, both mark the trace of the deep-seated structural breaks that border individual lithotectonic terranes. Subduction-related, late Jurassic to Cretaceous composite batholiths and plutons of dominantly granodioritic composition subsequently intruded the collage of basement rocks.
The basement rocks of the Sierra Nevada Foothills Metamorphic Belt are divisible into three discrete north-northwest-trending belts separated by first-order, right-lateral wrench faults of great linear extent. Mesothermal lode gold mineralization occurs in all three belts. The majority of gold production has been from along the boundaries and within the Central Metamorphic Belt.
The Grass Valley Mining District within the Central Metamorphic Belt is laced by a braided system of first-order, right-lateral wrench faults that parallel the north-northwest regional structural grain. These wrench faults can be identified by the corridors of high strain and the discontinuous, linear bodies of ultramafic rock that intruded cold, upward along the deep-seated breaks. Individual wrench faults can be traced for up to 100 miles in some cases, and they generally separate individual accreted terranes.
Back to Top
PROPERTY GEOLOGY
The rocks underlying the Idaho-Maryland Mine property are divisible into five separate units ranging in age from late Paleozoic to late Cretaceous:
1. Late Paleozoic to Triassic meta-sediments of the Fiddle Creek Complex
2. Jurassic meta-volcanics and interflow sediments of the Lake Combie Complex
3. Later Jurassic ophiolitic assemblage of the Spring Hill Tectonic Mélange
4. Discontinuous later Jurassic Tectonic Mélange of the Weimar Fault Zone
5. Early Cretaceous dioritic intrusives.
The most important of these with respect to the gold mineralization at the Idaho-Maryland Mine is the Spring Hill Tectonic mélange.
Back to Top
SPRING HILL TECTONIC MÉLANGE
The late Jurassic Spring Hill Mélange comprises a chaotic assemblage of clasts dismembered from the Jurassic Lake Combie Complex and its underlying oceanic crustal basement. The Spring Hill Mélange was recently identified as a mappable lithotectonic unit in 1995 (Payne et al, 1997). It is a district-scale structure, which underlies a 4-mile area and dominates the property geology. The mélange unit is 4,200 ft wide, extends for 4 miles in a 300° orientation, and crosscuts the regional structural grain. The mélange is localized within a district-scale boudinage neck. The Grass Valley Fault defines its southern margin. All of the significant gold production from the Idaho-Maryland Mine was localized within the matrix and tectonic slabs of this unit.
The Spring Hill Mélange consists of serpentinized ultramafic rocks that contain a chaotic arrangement of tectonic clasts. The serpentinite matrix of the mélange is well foliated and highly deformed. Locally it is comprised of a talc schist or talc + chlorite schist assemblage. The tectonic clasts or fragments range from fist-size clasts to mega clasts up to 1.5 by 0.62 miles in dimension. The clasts will be referred to as "slabs" when discussed individually in this discussion. The Emgold geologic staff has named the larger slabs. The tectonic clasts represent dismembered material from the walls of the intruded oceanic crustal sequence.
Individual tectonic slabs are monolithologic to heterolithologic in composition. The Brunswick Slab is the largest, bordering the Idaho Mine to the south, extending eastward for 1.5 miles, and encompassing the Brunswick and Union Hill Mine workings. The regional-scale Weimar Fault abruptly truncates the slab on its east end. The Brunswick Slab is a thick sequence of intermediate meta-volcanic flows, flow breccias, lesser tuffs, and minor interflow sedimentary units correlative with the Jurassic Lake Combie Complex. The interflow meta-sedimentary units include red to green cherts, black carbonaceous slates to wackes, and rare marl beds. The Brunswick Slab hosts the Brunswick and Dorsey Vein Sets, and provides important controls for the Idaho and Morehouse Vein Sets.
Back to Top
PROPERTY STRUCTURAL GEOLOGY
Weimar Fault Zone (6-3 Fault)
The Weimar Fault truncates all structures of the Idaho-Maryland Mine and forms the blunt eastern termination of the wedge-shaped ore deposit. The fault likewise truncates the eastern end of the Spring Hill Mélange unit. The Weimar Fault strikes 330° to 350°, dipping 70° northeast through the eastern side of the property. It is poorly exposed due to the gouge and highly comminuted nature of the rocks within the fault zone. The surface trace of the Weimar Fault, near the New Brunswick shaft, was a gougey serpentinite with the consistency of modeling clay. The Weimar Fault intersects the New Brunswick vertical shaft just above the 580 level stations. It is reported that the fault did not create any instability in the shaft, but that the shaft walls belled-out at that location where the rock broke to fractures. Underground, the Weimar Fault was intersected in many crosscuts and core holes. In all cases, the fault zone displayed strong shearing and gouge development.
Spring Hill Mélange
The Spring Hill Mélange unit is a dominant structural feature at the Idaho-Maryland Mine. This unit underlies a large portion of the mineral rights area. In the geological context of the Grass Valley Mining District, the Spring Hill Mélange and the Idaho-Maryland ore deposit cut the structural grain of the district at an obtuse angle. The Spring Hill Mélange unit is elongated in a 300° direction for 4 miles and has an average width of 0.87 miles. It has a pervasive fabric plunging 20° southeast at all scales. The Grass Valley and Olympia Faults confine it on its southern and northern boundaries, respectively. The matrix of the mélange is sheared serpentinite enclosing large exotic slabs of Jurassic Lake Combie Complex metavolcanics and its underlying oceanic crust. The internal structural elements within the mélange control the locations of mineralization in the mine. Individual tectonic slabs have shown important controls localizing vein sets and the Idaho Deformation Corridor.
Back to Top
IDAHO DEFORMATION CORRIDOR
The Idaho Deformation Corridor is a braided zone of high strain that extends along the entire length of the Idaho-Maryland ore deposit. The corridor averages 490 ft in width and is traceable for 2.0 miles along a 275° to 290° strike. The zone dips 60° to 70° south and extends to the deepest levels of the mine at 0.62 miles. The Brunswick Slab defines the southern boundary of the high-strain zone for nearly its entire length. The L Fault forms the northern boundary. In general, the zone exhibits a dominant normal vertical displacement with a much weaker component of right-lateral horizontal displacement. The linear fault members such as the Idaho and H Faults serve as the glide planes along which sheared plates of meta-volcanic rock slid upward. The link faults, such as the Idaho 2 Vein, are actually the preserved segments of the metavolcanic / serpentinite contact on the individual sheared plates. The ramp-like link faults may extend along their course upward through the serpentinites beyond the extent of the sheared plates of meta-volcanic slab. The points of dislocation marked by link faults along the contact of the Brunswick Slab are an important locus for the development of individual vein sets. The Maryland Vein Set is a prime example. The entire arrangement of faults and sheared plates of the Brunswick Slab suggest a fault duplex coupled with attenuation and incipient boudinage development.
Back to Top
MOREHOUSE FAULT
The Morehouse Fault branches from the hanging wall of the Idaho Deformation Corridor and follows the footwall contact of the Brunswick Tectonic Slab in a great arc. The Morehouse Fault outcrops poorly and has received only minor development in the mine. Mine development at the keel of the Brunswick Slab on the Idaho 1500, 2000, and 2400 levels has suggested that dislocations may occur in a pattern along the bottom contact (keel) of the slab. This has been interpreted from the arrangement and orientation of veins within the Brunswick Slab (Dorsey Vein Set), and outside of the slab (Morehouse Vein Set). Ramp-like dislocations along the contact, with fault structures extending into the slab, may explain the development of isolated groups of veins within the Brunswick Slab in the deeper developments of the mine. Vein set development outside of the slab may be associated with the same fault structures extending outward into the serpentinites from the dislocation site.
Back to Top
THE BRUNSWICK 20 SERIES FAULTS
The 20 series of faults exert locally important controls on oreshoots in the Brunswick Vein Set. The crossing of Brunswick Veins by members of the 20 Fault set can limit oreshoots in some cases, but is not a persistent feature in most areas of the Brunswick workings.
The 20 Faults, in conjunction with a Brunswick vein crossing a bed of interflow graphitic meta-sediments, result in a black slate-type oreshoot of large dimensions. The Brunswick 7 and 12 Veins appear to be dragged and horse-tailed against one of these cross faults, resulting in 40 to 55 ft wide quartz stringer zones. Adjacent Brunswick Veins are relatively unaffected in comparison. The 20 Faults locally contain mineralized vein quartz in a similar fashion to that noted in the Weimar Fault.
Back to Top
THE BRUNSWICK STACKED FAULTS
At the northeastern corner of the Brunswick Tectonic Slab is a stacked series of shallowly northeast-dipping fault/veins. They are associated with the junction of the Weimar Fault and the Idaho Deformation Corridor and are most commonly found within 1,000 ft of that wedge area. Well-known members of this vein/fault array are the Brunswick 4, 11, 34, 36, 41, and 48 Veins. Members of this fault set exert important controls on the location of exceptionally high-grade oreshoots and exceptionally large stockwork-veined deposits. Both deposit types occur where members or swarms of stacked faults disrupt the steep Brunswick Veins. Oreshoots in Brunswick veins will continue upward through an intersection of this type. It is consistently noted that strong gold mineralization will proliferate outward from the steep vein into the shallow dipping vein for distances of 50 to 100 ft laterally. Where the arrangement of steep Brunswick veins is close, this can result in large areas of stockwork veining that mimic the shape of the flatter structures. The intersection of the shallow-dipping Brunswick 4 Vein with the steep 7 and 17 Veins resulted in a shallow-dipping stope 200 by 400 ft in an area with a maximum true width of 50 ft.
Back to Top
GOLD RESOURCES
The Idaho-Maryland property hosts a significant gold deposit first discovered in 1851. Gold mining commenced in 1862 and continued until 1954. The varying styles of mineralization present at the Idaho-Maryland project are typical of those commonly found in mesothermal lode gold deposits worldwide. At least four basic types of mineralization have been recognized to contain significant gold deposits. In order of importance these include: 1) gold-quartz veins, 2) mineralized black slate bodies, 3) mineralized diabasic slabs, and 4) altered, mineralized phyllonites. The veins consist primarily of quartz, which is milky white, massive to banded, sheared, and brecciated. Gold occurs as native gold, ranging from very fine grains within the quartz to leaves or sheets along fractures.
The Idaho-Maryland gold resources are divided into five main groups the Eureka, Dorsey, Idaho, Brunswick and Waterman as shown in the following diagram:
Resource Area Map
Back to Top
INDUSTRIAL MINERAL RESOURCES
The industrial minerals ceramics feedstock resource was delineated by seven getechnical core holes drilled at inclinations of 40° and 45°, one exploration core hole, seven surface sample sites, and certain geologic data from historical underground mine drifts. The top boundary of the resource is 200 ft below the ground surface (due to depth of mineral rights). Drill hole spacing ranged rom 80 ft to 1,200 ft. The lower boundary of the resource is based on the bottom of the drill holes, since drilling ended within Lake Combie Complex igneous rock units. The west boundary is where the amount of gabbro and ultramafic rocks begin to increase. The east boundary is based on the limit of geotechnical drilling and surface sampling.
The Idaho-Maryland project has measured, indicated, and inferred industrial minerals (ceramics) feedstock resources, as follows:
|
INDUSTRIAL MINERALS RESOURCES - November 5, 2004 |
|
|
|
|
Classification |
Tons |
|
|
Measured mineral resources |
48,817,000 |
|
Indicated mineral resources |
122,685,000 |
|
Measured + Indicated mineral resources |
171,502,000 |
|
Inferred mineral resources |
358,112,000 |
|
Back to Top
GOLD EXPLORATION
Emgold initiated exploration of the Idaho-Maryland property in 1993. Emgold's wholly owned subsidiary, Idaho-Maryland Mining Corporation has continued exploration to the present. The primary focus has been to identify gold mineralization with the objective of developing a mineable gold resource.
The gold exploration program has consisted of an extensive geologic evaluation of the historical mine records plus additional diamond drilling from surface. This rather unique
program was possible because of the excellent and comprehensive preservation of the historical Idaho-Maryland mine and mill records. Idaho-Maryland has indicated this data is exhaustive and essentially complete, and was used to generate a consistent, propertywide structural geology model and vein set definition and chronology. Unmined mineralization was identified along underground workings and in historical diamond drill holes. Interpretation of the updated geologic model defined new vein sets and extensions of known vein sets. These were categorized for mineral resource estimates, future exploration, and expansion.
There is potential to identify additional gold resources on the Idaho-Maryland property, and Idaho-Maryland management has indicated its intent to continue with an ongoing gold exploration program. An access ramp is planned to establish underground drilling stations for further drill testing of key gold target areas, plus definition and expansion of known gold resources.
The revised Idaho-Maryland geologic model allows Emgold to evaluate areas among the known structures and veins for new vein set targets. Carefully designed multiple drill hole programs will be necessary to effectively test these targets in light of the complex geology and variable geometry of the mineralized veins. A schematic of the types of targets available are represented in following Figures.
Property Structural Geology - Plan View
Idaho-Maryland Mineralization Types
Exploration targets and the potential for new discoveries at the Idaho-Maryland project can be divided into seven large groups according to the dominant structure controlling mineralization. The structural features listed in order of decreasing importance are (1) the Idaho Deformation Corridor, (2) large individual mélange slabs, (3) Weimar Fault, (4) Morehouse Fault, (5) Clipper Creek Thrust, (6) Golden Gate Antiform, and (7) the Grass Valley Fault. Each structural feature has specific targets in known veins and further conceptual geological targets. However, although additional testing from surface can still be done, most of the exploration and delineation effort towards identifying additional gold mineralization will have to be executed from underground stations. The best areas for relatively shallow, higher-grade mineralization occur around the Idaho and Eureka shafts, south of the Round Hole shaft, and Loma Rica Ranch, based on the reinterpreted geology and occurrence of inferred resource blocks. Access for the initial underground drilling would be from the proposed exploration/production decline.
Back to Top
INDUSTRIAL MINERALS EXPLORATION
More recently, Emgold identified and secured rights to a new potentially commercial ceramics manufacturing process and realized that the Idaho-Maryland property may host mineral resources suitable as feedstock for the process. Initial investigations of the metavolcanic rock was started in June 2004 with a geotechnical drilling program designed to obtain data for the design of a mine access ramp. Geological information from this program was also analyzed to determine if the rock excavated during ramp construction would be suitable feedstock for the ceramics process. The analysis included surface geologic mapping, outcrop sampling, sampling of the diamond drill core, and testing of samples to assess their suitability for ceramics manufacture. The result of these analyses was the definition of a large volume of igneous rocks of similar composition that were considered satisfactory as an industrial mineral resource suitable for ceramics manufacture.
The industrial rock resource is adequately defined by core drilling, but further testing, marketing, and production of ceramic products using the Ceramext™ Process, and the beginning of underground development will be necessary to upgrade industrial rock resources into reserves. No further core drilling of the meta-volcanics is planned until access is developed underground.
Back to Top
2003/2004 DRILLING
Drilling from surface sites were completed in three phases: summer 2003 (gold targets), spring 2004 (gold targets) and summer 2004 (geotechnical and ceramic feedstock data).
Drilling totaled 21,335 ft in 31 drill holes for gold exploration and 3,537 ft in 7 drill holes for the geotechnical and ceramics feedstock work. A list of the project drill holes, together with their coordinates and lengths, is provided in Table: Idaho-Maryland Project 2003 and 2004 Drill Holes. Drilling was done by wireline method with H-size (HQ, 2.5 in nominal core diameter) equipment using a single drill rig. Collar locations of the core holes were surveyed with a GPS unit. Downhole surveys of all core holes were conducted at 100 ft intervals. Additionally, the geotechnical drill holes were drilled using oriented core (EZ Mark oriented core device). Upon completion, the collar and anchor rods were removed and the hole was abandoned to California regulation standards, and the site rehabilitated. Standard logging and sampling conventions were used to capture information from the drill core. The core is logged in detail onto electronic MS Access logging "sheets", and the data was then transferred into the project database. The core was digitally photographed before being sampled.
Idaho-Maryland Project 2003 and 2004 Drill Holes
AMEC Americas Ltd. reviewed the core logging procedures at site and the drill core was found to be well handled and maintained. Material was stored under cover (in a secure warehouse facility) in core racks. Data collection was competently done. Idaho-Maryland maintained consistency of observations from hole to hole and between different loggers by conducting regular internal checks. Core recovery in the mineralized units was excellent, usually between 95% and 100%. Very good to excellent recovery was observed in the mineralized intrusive sections checked by AMEC. AMEC judged that the overall Idaho-Maryland drill program and data capture were performed in a competent manner.
Back to Top
GOLD MINERALIZATION TARGETS
Drilling on gold targets was carried out from two locations (sites A and B, about 1,500 ft apart, see Figure: Surface Drilling Locations and Figure: Long Section of Drill Sites A and B) and tested various blind structural targets.
Surface Drilling Locations
Long Section of Drill Sites A and B
Key findings from the drilling are:
- Confirmation of the serpentinite - matrix tectonic melange zone geologic model for the Idaho-Maryland Mine. The localization of gold-quartz veining (1) along melange slab contacts and (2) in association with bench dislocations along the Brunswick Slab contact was also corroborated.
- Nearly all gold is coarse particulate in nature and confined directly to vein quartz and phyllonites of the vein shears. Values were tightly confined to structures with little or no dispersion of gold into the wallrocks. Coarse particulate gold was also identified within micro-fractured diabase and serpentinite adjacent to very strong mineralized faults. Chloritization, the associated destruction of the crystalline igneous textures, and development of porphyroblastic pyrite overgrowths are diagnostic for the auriferous diabases.
- In 2003, the drilling intersected high-grade mineralization at depth in the Idaho 120 Vein, several hundred feet beneath an outcropping barren carbonate alteration bloom (see Figure: Drill Hole Cross Section - Looking S40E). Hole IDH001 cut 10.1 ft @ 0.93 oz/t Au in a complex vein structure. In 2004, follow up drilling tested westward and at higher elevations from the highgrade intercept. Evidence of old mining was seen at higher elevations whereas the mineralization quickly pinched off to the west. The drill position would not allow testing to depth and eastward thus the target remains open along strike and down rake to the east. Further delineation of this target will be planned for the 2005 surface drilling program.
- Drilling revealed that the keel of the Brunswick Slab is shaped different than anticipated. Hole IDH006 did not intersect the Idaho 1 Vein at the keel of the Brunswick Slab, where it was projected to occur at 1,000 ft depth. This implies a steeper plunge for the keel from surface to 1,100 ft depth and a considerable flattening of the plunge below 1,100 ft depth, and extending eastward toward the Idaho 1500 Level.
Drill Hole Cross Section - Looking S40E
Significant intervals intersected in the 2003 and 2004 drill campaigns testing gold mineralization potential are shown in Table: Significant Gold Mineralization Intersections, 2003-2004 Drill Campaigns.
Significant Gold Mineralization Intersections, 2003-2004 Drill Campaigns
Back to Top
GEOTECHNICAL DRILLING (CERAMICS FEEDSTOCK DEFINITION)
Geotechnical drilling was conducted to obtain ground stability data for the proposed mine access ramp. Holes were angled downward at 40° to 45° from the horizontal to maximize the areas examined in the directions of the decline route. In
addition, data were obtained to determine the usability of the block of meta-volcanic rocks for ceramics production. All drilling was contained in the Brunswick Slab. The dominant rock types intersected were andesite volcanic flows, flow breccia, and hypabyssal feeder units intruded by diabase intrusive units. Chemically they are quite similar and would be considered all the same unit with respect to ceramics production. Gabbro units were intersected around the proposed portal area but otherwise only constitutes a minor component of the drilled region. Visually quite distinctive, the gabbro could easily be segregated during mining should it become necessary. A key observation in all the drill holes (outside the weathered surficial zone which will not be considered for
ceramics production) is the general absence of any broken core and/or gouge intervals, foliated or sheared zones, and fractured or veined areas. The core area of the Brunswick
Slab is shown to be a massive, undeformed, essentially monolithic unit of mafic composition.
Back to Top
GOLD MINERALIZATION SAMPLING METHOD AND APPROACH
Sampling of the half cores was performed by Idaho-Maryland staff in a secure core logging and storage facility. Sample size was critical due to the coarse particulate nature of the gold (The sample size was optimized to allow for multiple check assays, if required, as the use of large assay pulps was necessary). The target sample size was 3 ft, with the minimum being 2.5 ft, and 3.3 ft the maximum.
The core ends would be matched through all of the boxes, and fractured sections wrapped in duct tape to preserve geological information and reduce core loss during the cutting process. Core was halved with a wet saw, using continually running fresh water, and cut along the same line of orientation, which provided excellent angular relationship data for structural geologic interpretation. When strongly mineralized sections of core were cut, a plastic tray was inserted into the saw pan and saw cuttings were collected and panned. The pannings were helpful in alerting staff to the presence of coarse gold and assisted in the review of assay and check assay results.
The half cores within a marked sample interval were put in a sample bag, tagged, and loaded into 55 lb (25 kg) shipping sacks and secured. The samples from the split core remained in the logging facility until shipped to the assay laboratory. Samples were shipped in one of two manners. Idaho-Maryland staff transported samples to the assay labs in Nevada or the representatives from the assay lab came to the Idaho-Maryland facility to pick up samples, depending on the sizes of the shipments. The majority of the samples were shipped to American Assay Laboratory in Sparks, Nevada and check assays were sent to the Barrick Goldstrike Laboratory in Carlin, Nevada.
Back to Top
CERAMIC FEEDSTOCK SAMPLING METHOD AND APPROACH
All cores were cut in half with a diamond saw at Idaho-Maryland's core logging facility. The half cores were primarily collected to conduct whole rock analyses of different rock
types and extrusion testing into billets. Remaining half cores were combined into a bulk composite sample for ceramic production testing.
Back to Top
GOLD SAMPLE PREPARATION, ANALYSIS AND SECURITY
The primary sample preparation and analyses were performed by American Assay Laboratory of Sparks, Nevada. Historic records for the Idaho-Maryland mine noted coarse gold in all ore types, thus Idaho-Maryland chose to be conservative and have all samples analyzed using screened metallics fire assay methods. The flowchart of the preparation and analysis process is shown in Figure: Sample Preparation and Assay Procedure Flowchart. The laboratory prepared two pulps from each sample. One 500 g sample was for fire assay analysis and a 100 g pulp was prepared and returned to Idaho-Maryland for gold panning. Panning of the 100 g pulp by Idaho-Maryland staff provided (1) a cursory check on the lab, (2) allowed collection of gold particle size, shape, and population information, and (3) helped direct the ongoing core drilling program when lab analysis turn-around time was slow. The 500 g pulp was analyzed for gold only, utilizing screened metallics fire assay methods. All pulps and coarse rejects were saved by the lab and delivered back to the Idaho-Maryland core facility.
Sample Preparation and Assay Procedure Flowchart
A rigorous QA/QC program has been developed and utilized at the Idaho-Maryland Project. Extra precautions were taken by Idaho-Maryland staff to mitigate the potential for assay variability due to the frequent coarse gold occurrence in the mineralization. The program used Standard Reference Materials (SRMs), blank samples (made from barren massive antigoritic serpentinite), coarse reject and pulp duplicate samples and third party laboratory check assays. Insertion rate of SRMs and duplicates was about 1 in 20 samples. Blanks were only inserted immediately following mineralized intervals. The SRMs were prepared from gold mineralized material of varying grades, collected from a nearby gold mine to formulate bulk homogenous material. Two groups of material were collected: one with a mean certified value of 0.21 oz/ton Au and the other with a mean
certified value of 0.17 oz/ton Au. These materials were used to successfully control the assay quality process. Blank sample results showed no evidence of gold contamination during sample preparation. One anomalous sample result was due to a sample mix-up; it was checked and corrected in the final database.
Duplicate performance was good to fair, reflecting the coarse particulate nature of the gold mineralization. Performance was worse closest to the detection limit. Patterns on control charts were symmetric about zero, suggesting no bias in the assay process.
Four criteria were used in selection of samples for third party laboratory check assays. These were (i) all assays equal to or greater than 0.01 oz/ton Au, (ii) all samples with free gold panned from 100 g pulp sample regardless of assay value, (iii) all samples with visual similarity to oretypes regardless of assay value, and (iv) 5% of the remaining sample population selected randomly. Results mirrored the primary laboratory duplicate analyses.
AMEC reviewed Idaho-Maryland's QA/QC procedures at site and found them to be strictly adhered to. The gold assay process for the 2003 and 2004 drill campaigns were shown to be in control. The rigorous assaying methodology employed during the these phases of drilling identified mineralization types which will require screened metallics fire assaying in future work. These oretypes include samples containing (i) over ten percent vein quartz, (ii) green chloritized diabase with porphyroblastic pyrite overgrowths, (iii) phyllonites with porphyroblastic pyrite overgrowths, and (iv) about 3 ft of wall rock immediately preceding and after any of the first three types.
Back to Top
CERAMIC FEEDSTOCK SAMPLE PREPARATION, ANALYSIS AND SECURITY
Samples were submitted to Kappes, Cassidy and Associates and Florin Analytical Services, LLC in Reno, Nevada for preparation and geochemical analyses. Tests were conducted to determine the elemental content of each rock type for optimizing the ceramics extrusion process. The whole rock analysis test involved pulverizing the sample to minus 150 mesh, conducting lithium metaborate fusion followed by nitric acid digestion, and semi quantitative ICP analysis for elements, oxides, and loss on ignition. The results were reported as percentages with and without the weight of oxygen. Measurements of total and organic carbon and total sulfur were made utilizing the Leco furnace method.
Extrusion tests were conducted at the Idaho-Maryland ceramics testing facility in Grass Valley, California. Samples were first sent to Kappes, Cassidy and Associates for grinding to minus 100 mesh, and then retrieved by Idaho-Maryland personnel. Representative samples of the rock types were extruded into ceramic plugs using the laboratory-scale extrusion plant. Positive results were achieved for meta-volcanic and diabase samples. Gabbro samples did not perform well and will have to be blended should it become part of the feedstock material. Testwork has indicated that a 9% gabbro content in the ceramic feedstock is acceptable, and testwork is ongoing.
The specific gravity of the rock was measured by Vector Engineering of Grass Valley, California using ASTM method C127 on representative pieces of drill core and surface samples.
Back to Top
CAUTIONARY NOTE TO U.S. INVESTORS
Cautionary Note to U.S. Investors concerning estimates of Measured and Indicated Resources.
This website may use the terms "measured resources" and "indicated resources." We advise U.S. investors that while such terms are recognized and permitted under Canadian regulations, the U.S. Securities and Exchange Commission does not recognize them. U.S. investors are cautioned not to assume that any part or all of the mineral deposits in these categories will ever be converted into reserves.
Cautionary Note to U.S. Investors concerning estimates of Inferred Resources.
This website may use the terms "inferred resources." We advise U.S. investors that while such term is recognized and permitted under Canadian regulations, the U.S. Securities and Exchange Commission 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 feasibility or other economic studies. U.S. investors are cautioned not to assume that any part or all of an inferred resource exists, or is economically or legally mineable.
|
|
S.E.C. Industry Guide |
National Instrument 43-101 |
|
|
Reserve: That part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination. The United states Securities and Exchange Commission requires a final or full Feasibility Study to be completed in order to support either Proven or Probable Reserves and does not recognize other classifications of mineralized deposits. Note that for industrial mineral properties, in addition to the Feasibility Study, "sales" contracts or actual sales may be required in order to prove the project's commerciality and reserve status. |
Mineral Reserve: The economically mineable part of a Measured or Indicated Mineral Resource demonstrated by at least a Preliminary Feasibility study. This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified. |
|
|
Proven Reserves: Reserves for which a quantity is computed from dimensions revealed in outcrops, trenches, workings or drill holes; grade and/or quality are computed from the results of detailed sampling and measurement are spaced so closely and the geologic character is so well defined that size, shape, depth and mineral content of reserves are well established. |
Proven Mineral Reserve: The economically mineable part of a Measured Mineral Resource demonstrated by at least a Preliminary Feasibility study. This study must include adequate information on mining, processing, metallurgical, economic, and other relevant factors that demonstrate, at the time of reporting, that economic extraction is justified. |
|
|
Probable Reserves: For which quantity and grade and/or quality are computed from information similar to that used for proven reserves, but the sites for inspection, sampling and measurement are farther apart or are otherwise less adequately spaced. The degree of assurance, although lower than that for proven reserves, is high enough to assume continuity between points of observation. |
Probable Mineral Reserve: The economically mineable part of an indicated, and in some circumstances, a Measured Mineral Resource, demonstrated by at least a Preliminary Feasibility Study. This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified. |
|
Back to Top
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
