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28 SEG NEWSLETTER No 91 • OCTOBER 2012 Oregon SEG Student Chapter STUDENT NEWS Field Trip to Southeastern Oregon and Northern Nevada June 18–21, 2012 The Oregon student chapter, including Oregon State University (OSU) and the University of Oregon (UO), organized a four-day field trip to examine epithermal Hg-Au deposits in eastern Oregon and northern Nevada and to visit a Carlin-type gold deposit at the Marigold mine, at the northern margin of the Battle Mountain-Eureka trend in Nevada. An assorted group of graduate and under graduate students from both schools participated, as well as a visiting scientist from Iran. During a twohour pre-trip seminar, we discussed some of the re gional geology and mineralization types that we would be seeing while on the trip. The trip focused on three broad themes: (1) general geology of the High Lava Plains (HLP) and northwestern Basin and Range of Oregon and associated geothermal activity, (2) Hg-Au epithermal, steam-heated quartz-alunite alteration and associated cinnabar mineralization and (3) a visit to the Marigold mine in northern Nevada. The general geology of the HLP segment included stops at two phreatomag - matic eruptions, crescent dune formation and wave cut terraces in the Warner Valley, poorly sorted landslide deposit shed off the Winter Rim fault and the Glass Buttes rhyolite dome complex on the Brothers fault zone. We also had the opportunity to camp at two hot springs, Crystal Crane and Hart Mountain. Glass Buttes (HLP) was mined for mercury in small quantities from the 1950s to 1973 in pervasive silica sinter deposits. This is also the site of an ongoing geothermal prospect (Ormat). Oregon student chapter members at the Marigold mine, northern Nevada. Left to right: Matt Loewen (OSU), Mark Ford (OSU), Chris Gibson (OSU), Kevin McCartan (UO), Tim Stimpson (UO) and Goldcorp geologist Greg Eisen. Our second day was spent in the area of the Buckskin National mine, just south of the Oregon-Nevada border, Tim Stimpson (left–UO) and Chris Gibson (right– OSU) discuss the brecciated silicic cap and cinnabar mineralization at Glass Buttes, Oregon. which is another epithermal system. Buckskin Mountain is capped by a thick package of silicic sinter with vein de - posits, mined primarily in the 1920s and 1930s. The pinnacle of the trip was a visit to the Marigold mine (jointly owned by Goldcorp and Barrick) where we got a great, all-encompassing tour and discussion of Carlin-type gold deposits from chief geologist James Carver. This visit to a large, active mine was a first for many in the group and it was a wonderful learning experience. We would like to extend a thank you to the seminar speakers, Luc Farmer, Mark Ford and Steffi Waffron, and to faculty advisor John Dilles for his support. We would like to extend a special thank you to James Carver, Greg Eisen, and Dan Deveny of the Marigold mine for their tour. A special thanks also goes to SEG for providing financial support. Mark Ford 1 Dale Sims Geologist FAusIMM CP(Geo), MAIG, FSEG Resource and mining geology, project reviews, training, 3D modelling and data analysis. Specialising in Leapfrog and Vulcan modeling software. Email: dalesims@tpg.com.au Ph: +61 (0) 2 4930 1927 Mob: +61 (0) 457 405 229 PAID ADVERTISEMENT PAID ADVERTISEMENT
OCTOBER 2012 • No 91 SEG NEWSLETTER 29 EXPLORATION REVIEWS Notice: Views expressed in the Exploration Reviews do not necessarily reflect those of the Society of Economic Geologists, Inc., and columnists are solely responsible for ascertaining that the information in this section is correct. To read additional exploration reviews for countries, visit www.segweb.org/newsletter for SEG Newsletter supplement. ALASKA Regional Correspondent: Curtis J. Freeman (SEG 1996) Avalon Development Corp. P.O. Box 80268 Fairbanks, AK 99708 Tel. 907-457-5159, Fax 907-455-8069 E-mail: avalon@alaska.net Website: www.avalonalaska.com More than a year ago, Natural Resource Holdings published a report, entitled “How rare are one million ounce gold deposits?” At that time, they summarized 296 gold deposits that have more than 1 Moz of gold in all resources categories. The same firm recently published a more comprehensive follow-up report, entitled “Global gold mines & deposits 2012 ranking.” The new report ranks gold deposits above 1 Moz with numbers that have increased to 439 deposits with total resources of 3,015,542,164 oz of gold. Some new factoids involving Alaska were brought out by this study. For example, there are only 33 gold deposits in the world that have +20 Moz and Alaska has three of them: Pebble (at 107.3 Moz, ranked no. 1), Donlin Creek (45 oz, ranked no. 10) and Liven - good (20.6 Moz, ranked no. 31). Alaska also had four other +1 Moz deposits on the list—Fort Knox, Whistler, Vinasale, and Golden Summit. Casting a little doubt on the reliability of this study was its exclusion of Alaska’s largest operating gold mine, Sumitomo’s Pogo mine, where they just poured their 2-millionth ounce from a +5 Moz pre-mine resource and Alaska’s newest, the Coeur d’Alene Mines Ken - sington mine, with published resources of 1.3 Moz. To add insult to injury, I know of at least two other Alaska deposits with published gold resources of +1 Moz that for some reason did not make the final list. Okay, so the study was not perfect but neither did it claim to be. Regardless of the shortfalls in the report, those 33 +20 Moz deposits, comprising only 7.5% of the total number of +1 Moz deposits, contain over 41% of the world’s total gold resources. More sobering was this fact: the average producing gold mine today has a head grade of 1.06 grams of gold per tonne. However, the average grade of all undeveloped gold deposits is only 0.82 grams of gold per tonne (37% lower). The conclusion here is clear: even if we try to maintain current gold production rates, costs are going to rise because we’ll need to mine and process 37% more rock than we do today. Perhaps even more important is the finding that the increased price of gold in the last several years has had no effect on the rate of new gold discoveries. The current producers, many of whom are also producing from +1 Moz deposits, churn out 90 Moz of gold per year. Assuming that this production figure is maintained and, barring the unlikely possibility that multiple high-grade, multimillion-ounce discoveries will occur every year, the report indicates that “peak gold” production will occur between 2022 and 2025. Time will tell whether “peak gold” will be as elusive to pin down as “peak oil” has been. AUSTRALASIA Regional Correspondent: Russell Meares (SEG 1996) Malachite Resources Limited Sydney, Australia E-mail: rmeares@malachite.com.au Website: www.malachite.com.au With contributions from Roger Thomson (SEG 1983) Western Australia Lucy Chapman (SEG 2000)–Queensland Tony Christie (SEG 1992)–New Zealand Geoff Green (SEG 2000)–Tasmania Steve Russell (SEG 2009)–NT Peta Abbot–South Australia Bianca Pietrass-Wong–NSW Peter O’Shea–Victoria SUMMARY News of a significant greenfields Ni-Cu discovery in a poorly explored remote mineral province is welcome to an exploration industry that is constrained by an aversion to risk by investors in the currently nervous global markets. Sirius is the brightest star in the sky, and it was the announcement by Sirius Resources of the first drill hole at its Nova prospect in the Fraser Range province in the southeast of WA that saw the share price skyrocket from 6c to 56c—a stellar result, indeed! The hole was testing the source of a 1 km × 300 m EM conductor and intersected a body of massive sulfides (pyrrhotite-pentlandite-chalcopyrite) that assayed 4 m @ 3.8% Ni and 1.42% Cu from 191 m. The second hole intersected 15 m of matrix to massive sulfide up-dip from the discovery intersection and assay results are awaited. The discovery was made beneath transported overburden and is well located, less than 40 km from the port of Esperance on the south coast of WA. See further details in the WA report by Roger Thomson in the online version, where other exploration news from Down Under appears. Our Queensland correspondent (Lucy Chap - man) has also written a very comprehensive update of exploration news from her State. Elsewhere on the Australasian scene, explorers are winning on some fronts and losing on others. There has been a swing to elect conservative pro-business State governments in recent elections, and they are progressively recognizing that the local exploration and mining industry is hampered by bureaucratic red tape resulting in time delays and excessive costs to the industry. One of the first governments to respond has been recently elected Queensland, which has introduced legislation to cut red tape by 20% and to streamline the tenement management and approvals process. Victoria is also conducting a review of ways to cut red tape and make the State more attractive to explorers. On the other side of the coin, Aus - tralia’s gold output declined for the third consecutive quarter, ending March 2012, to 62 tonnes (in line with our “gold medal drought” at the London Olympic Games!). This decline was partly in response to the to page impact of unseasonal 30 ... EXPLORATION REVIEWS
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