Roca Mines Inc.

Project Review 2003


Roca's Foremore Project is well located; centred 45km north of Barrick Gold Corporation's legendary Eskay Creek mine and 30km east of Novagold's Galore Creek Project, in northwestern British Columbia. Eskay is one of Canada's richest gold-silver producers with 2003 production of 352,000 ozs. gold, and 17,000,000 ozs. silver at a cost of $52/oz. gold. Eskay is accessible by road from the community of Bob Quinn Lake on paved Highway 37 located 45km east of the mine. An airstrip at Bob Quinn provides access for flights from the town of Smithers, 320km southeast.

The Foremore comprises 54 claim blocks (824 units) covering approximately 206 and encompasses an abundance of known precious and base metal rich mineralized boulder fields, mineralized outcrops, and geochemical and geophysical showings in several target areas.


Cominco Limited staked portions of the current Foremore Property area after the discovery of a gold-rich (5.2 oz./ton Au) quartz boulder and several massive sulphide boulder fields during helicopter reconnaissance in 1987. Subsequent exploration work by Cominco was conducted to determine the source of over 1000 mineralized boulders, many of which display volcanic-hosted massive sulphide (VHMS) characteristics, found in the North (NBF), South (SBF), Side Glacier (SGBF) and East Boulder Field (EBF). Strong UTEM geophysical conductors located under the More Glacier were subsequently diamond drilled, a total of six holes that failed to intersect mineralization of interest. Cominco carried out a total of over C$2m of work on the property during 1987 -- 1992 and subsequently in 1996 prior to the claims lapsing in 1999. Roca's property vendor, Mr. L.B. Warren then staked a large land package over the boulder fields and many of the geophysical conductors. Roca optioned the property and is earning a 100% interest in the property by conducting exploration work and by making cash and share payments.

Field Work 2002-2003

In May 2002, Roca began detailed research on the Foremore area geology, a comprehensive data compilation and an air-photo interpretation study. That work resulted in the definition of a number of new targets areas for mineralization that had not been recognized or pursued by Cominco in the past. Equity Engineering Limited was then contracted to carry out a summer 2002 field program that consisted of geological mapping, prospecting and geochemical sampling specifically focused at the target zones identified from the review. In addition to their efforts during the field season, Equity also prepared a qualifying report on the property which was summarized and filed with Roca's IPO prospectus offering.

As a direct result of Roca's targeting efforts and exploration activities, a number of mineralized zones, comprising several different mineralizing styles were identified on the property, including;
  1. SG Zone;
  2. North Zone (North Showing);
  3. Westmore Gold Zone; and,
  4. Hanging Valley Targets.

These mineralized zones were re-examined during an extensive 2003 field season (June through October) and during this time additional mineralized zones were found, including;
  1. BRT Showing (part of the North Zone);
  2. Sunday Zone
  3. Rhino Showing; and,
  4. Wishbone Area.

A review of our 2002 work program is included in the BC Ministry of Energy and Mines, Resource Development Division Exploration and Mining in British Columbia 2002. Related Extracts from this summary are provided in the file BCMEM-2002Report.pdf- available under the "Articles and Comments" menu heading.

VHMS Targets (SG Zone, North Zone, Rhino Showing)

SG Zone

The southwestern area of the SG Zone was the initial VHMS discovery during the 2002 field season. Roca's focus in locating the sources for the mineralized boulder field concentrated on the up-hill potential, rather than the up-ice potential. Prospecting and sampling north of the SGBF was conducted and resulted in locating the SG Zone "Discovery Showing". Following discovery, and to create larger exposures, drill and blast trenching was initiated and completed in September 2002, exposing larger areas of mineralization in between snow-filled gullies. Stringer type zinc, lead, gold and silver rich massive sulphide mineralization was exposed, but due to snowfall it was difficult to determine the nature of the mineralization. Assays of specimens collected at this time returned values of:
  • 20.11 g/t Au, 138 g/t Ag, 12.6% Zn, 11.2% Pb, and 0.14% Cu from an arsenopyrite-rich massive sulphide sample; and
  • 1.08 g/t Au, 158 g/t Ag, 9.0% Zn, 25.8% Pb, and 0.24% Cu from a galena-rich sample.

Significant snowmelt during the 2003 field season showed this mineralization to be in-place crosscutting stringer type and massive, yet probably positioned peripheral to more extensive and layered massive mineralization. Geologically, the exposed mineralization is hosted in the southwest portion of a rhyolitic "dome" along a stratigraphic interval containing many other isolated rhyolitic units. The thickening of the rhyolite toward the northeast is suggesting that this is the area where further exploration should be focused. Massive sulphide mineralization in VHMS environment is generally found flanking the thicker portions of a felsic dome.

The discovery of the SG Zone was historically the first identification of source rocks for one of the mineralized boulder fields. It was our belief that, having discovered one such source, others must also be present to account for the wealth of mineralized boulders on the property. In early 2003, the BRT discovery in the North Zone, upslope from the NBF, confirmed that belief.

North Zone

Mapping and prospecting at the North Zone was focused on sourcing precious metal rich zinc-lead VHMS mineralization in quartz-sericite-pyrite phyllites interfoliated with variable chloritic and sericitic phyllites. Roca's 2002 work confirmed that mineralization consists of thin foliation-parallel laminations and disseminations of pyrite, sphalerite and galena with lenses of semi-massive to massive pyrite in the quartz-sericite-pyrite phyllite at the North Showing, originally located by Cominco. Follow-up fieldwork in 2003 initially located massive sulphide boulders 1.2km along strike toward the northeast of the North Showing. These boulders were immediately sourced to the nearby creek exposure of massive sulphide named the BRT Showing. Assays from the boulders located near the outcrop ran as high as 95.9 g/t Au, 1964 g/t Ag, 7.3% Zn, and 5.8% Pb from a heavily oxidized portion of the massive sulphide.

The BRT Showing discovery outcrop is a 3m structurally thicken layer of gold and silver enriched massive sphalerite, galena, and pyrite with lesser chalcopyrite. Several channel samples were taken from the discovery outcrop and additional hand-dug trenches and contained the following high grade intervals:

Trench Interval (m) Au (g/t) Ag (g/t) Zn (%) Pb (%) Cu (%)
BRT-01 2.05 2.75 189.7 6.34 0.94 0.73
BRT-02 2.80 2.03 161.9 9.52 4.27 0.11
BRT-03 4.30 2.07 276.4 1.33 2.13 0.41
Including 0.65 7.61 554.6 7.44 11.58 0.14
BRT-04 1.20 0.27 44.7 -- -- --
BRT-05 4.0 1.90 137.3 0.14 0.24 --

Seven drill holes were completed over a portion of the stratigraphy hosting the BRT Showing. No high-grade massive sulphide mineralization was intersected; however hole FM03-11 assayed 7.92 g/t Au over 2.3m within a larger interval of 4.9m which assayed 4.37 g/t Au and 56 g/t Ag. Also, the quartz-sericite-pyrite unit hosting the massive mineralization at surface was intersected in all holes ranging from 10 to 32m in thickness, and is observed to be thickening with depth. Additional work is being focused on understanding the structure and orientation of the massive sulphide mineralization within the mineralized phyllite.

The North Zone is a likely source area for the extensive North Boulder Field (NBF) discovered by Cominco in the late 1980's. Cominco sampled two types of massive sulphide boulders identified in this boulder field and reported the following average assays:

Boulder Type Au(g/t) Ag (g/t) Zn(%) Pb(%) Cu(%)
Layered (29 samples) 1.0 96 10.2 3.5 -
Feeder (12 samples) 1.5 186 6.2 - 2.3

Samples from the BRT are similar to the "layered" samples and although the BRT samples have higher gold and silver values, texturally and mineralogically BRT outcrop samples are very similar. The BRT Showing is a probable source for the northern portion of the NBF. Copper-rich "feeder" samples have not yet been found in outcrop.

Rhino Showing

The Rhino is an exciting new showing discovered approximately 5km to the NNE of the SG Zone. Limited trenching by hand across the showing has outlined the Rhino showing as a large discontinuous layer or lens of massive pyrite, in excess of 4m thick and situated at a stratigraphic horizon similar to the SG Zone. Samples taken from the hand trenches assayed low base and precious metal values. Interestingly, a grab sample from glacial debris down slope from the showing returned 3.23 g/t Au and 34 g/t Ag, from an oxidized massive pyrite boulder.

The outcropping massive pyrite mineralization is hosted in limestone and occurs at a limestone/mafic volcanic contact, in the vicinity of felsic volcanics slightly higher in the sequence. The contact zone strike toward the NE and is upslope from a fairly cohesive Zn-Ba-Pb soil anomaly, with high sporadic Au (279 ppb) and Cu values (150 ppm).

The Rhino Showing is important in that when linked to the SG Zone, they define a 7km+ long strike length along which there is great potential for additional VHMS mineralization. Added to this the fact that VHMS mineralization typically occurs in clusters, this horizon will be a focal point for exploration in 2004.

Epigenetic Gold Targets (Wishbone, Westmore, Hanging Valley)

Wishbone Area

The Wishbone Area has just recently been defined and will no doubt grow in size and number of showings in 2004. Wishbone is defined by both the presence of spectacular visible gold in outcrop (Hollywood Showing -- select sample assay returning 3240.9 g/t gold and 82,514 g/t silver) and by an extensive, 2.5km long zone of boulders which return spectacular silver values as presented in the following table.

Sample # Sample Type*/SizeAu (g/t) Ag (g/t) Cu (%)
126483 o/c - fist sized specimen with visible gold 3,240.9 82,514 0.132
126518 flt - 15 cm boulder massive pyrite 1.21 315.1 1.103
126523 flt - 20 cm massive pyrite boulder 4.70 27.6ppm 0.029
126524 flt - 20 cm massive sulphide boulder 1.95 605.5 0.365
126525 flt - 25 cm iron carbonate boulder with 10% pyrite 2.28 2.5ppm 25ppm
126526 flt - 30 cm boulder massive sulphide 1.63 9.9ppm 6.497
126528 flt - 10 cm boulder with cp 2.47 48.4 8.223
126529 flt - 25 cm boulder with semi-massive pyrite & arsenopyrite 1.70 1,093.5 1.122
126533 flt - 10 cm boulder of semi-massive pyrite and tetrahedrite 0.20 4,835.1 3.504
126534 flt - 15 cm boulder of semi-massive pyrite, chalcopyrite and tetrahedrite 0.74 4,362.6 3.021
126539 flt - 10 cm boulder with band of massive pyrite and lesser tetrahedrite 0.15 6,708.3 2.546
126540 flt - 10 cm Fe carbonate boulder with tetrahedrite and pyrite 0.27 1,819.3 0.81
Note: flt = float, o/c = outcrop

The extensive Wishbone area is underlain by various argillaceous schists and phyllites, as well as cleaner quartz sericite phyllites, together representing a mixed felsic volcanic-sedimentary package.

The Hollywood Showing is a discontinuous, 5-7cm wide quartz-carbonate vein which contains spectacular visible gold as well as a very soft silvery gray mineral, inferred to be a silver telluride and/or native silver. The vein cuts across the local foliation and it is difficult to determine if it is related to the abundant folioform veins cutting the schists and phyllites.

Although this discovery vein is of limited size, it indicates that the extensive silver rich veins boulders down slope may also have a very gold rich counterpart. It is also unclear whether this mineralization is related to gold mineralization at Westmore, the other portion of the property where visible gold was found.

Westmore Gold Zone

The Westmore Gold Zone is an extensive area containing gold-bearing sheeted quartz veins hosted predominantly in post-Triassic intermediate to granitic intrusives (Westmore Stock), and less so in Devonian-Mississippian mafic volcanics. Cominco personnel found float boulders assaying as high as 162 g/t Au, and in-place grab samples running > 20 g/t Au. Roca collected a float sample returning 17.05 g/t Au and a chip sample containing 2.27 g/t Au and noted visible gold.

The vein sets trend east-west to southeast-northwest and are 0.25 to 2m in width. Thicker veins are composed of milky white quartz with minor coarse grained pyrite and thinner veins locally contain abundant sphalerite, galena, and chalcopyrite. At least two generations of veining are present at the Westmore Gold Zone.

Little work was done on Westmore during 2003 as the field season focus was on detailed work at the North and SG Zones and in prospecting on portion of the property that had not yet been visited. Roca intends to budget more time to prospecting and sampling the Westmore veins, generating drill targets as a result.

Hanging Valley Targets

The Hanging Valley is a relatively broad open valley rimmed by variably altered and mineralized Devono-Mississippian carbonate rocks intercalated with mafic to felsic volcanics. Widespread localized mineralization is present as copper±zinc±lead±gold bearing sulphide lenses and/or veins that generally occur as foliation parallel structures or as thin shear zones. Gold grades as high as 93.7 g/t (1m chip by Cominco) and 81.7 g/t (Roca grab) are present in a base metal rich vein on the north slope of the valley. The interlayered limestone and felsic volcanics are now recognized as likely equivalents to the stratigraphy hosting the SG Zone.

Much of the north slope of the valley was prospected in 2003, resulting in the discovery of the Sunday Zone. Due to its stratigraphic position and proximity to the More Creek Pluton, other epigenetic (skarns, mineralized shears) and syngenetic (VHMS) targets are possible in the Hanging Valley, and it represents an area favourable for sourcing the South Boulder Field.

Exploration Potential and Planned 2004 Field Work

The Foremore Property lies within the Stikine Terrane, an extremely rich metallogenic belt that is a product of prolonged island arc volcanism. This world-famous belt hosts a number of very significant present and past producing mines, displaying a wide variety of genetically related mineralization styles, including:
  • Porphyry Copper-Gold-Molybdenum - Schaft Creek, Galore Creek, Kerr/Sulpherets;
  • Intrusion related mesothermal veins - SNIP and Johnny Mtn. gold mines, Red Mtn;
  • Epithermal gold-silver veins - Sulpherets, Newhawk, Premier Mine, Golden Bear Mine;
  • Volcanic Hosted Massive Sulphide - Eskay Creek, Tulsequah Chief, Granduc.

The most economically significant type of mineralization on the Foremore Property is precious metal enriched VHMS type mineralization. The SG and North Zones, along with the Rhino Showing, share many mineralogical and grade characteristics with world-class VHMS deposits.

Exploration work to date over the Foremore Project by Roca and others consisted of tried-and-true exploration techniques including prospecting, geological mapping, rock/soil/silt sampling, ground geophysics and diamond drilling. The most recent work by Roca has been very successful in finding new mineralized zones as well as increasing our understanding of known mineralized zones.

Roca's 2004 focus will follow on the successes of the 2003 field work. Added geological understanding of the North and SG Zones has allowed Roca to plan extensive diamond drill program across these zones. Less well known showings will also be advanced and diamond drilled. A 2 phase drilling program through the summer will amount to upwards of 10,000m, most of which will be directed at SG and North Zones. As always, prospecting, mapping, and sampling will continue across the whole of the property and ground based IP ± Mag will be directed toward the North Zone. Sourcing of additional enigmatic boulder fields will continue.