Atomic Emission Spectroscopy

Global Announces High Grade Silver Intercepts at Strieborná

The Company believes that this is the first time the Strieborná vein has been analyzed for gold. The presence of gold may provide an additional credit if recovered in concentrates and will now be considered in future economic assessments.

"The drill results are promising and support the current resource model and respective grades, said William Bond, VP Exploration for Global.  "The drill program was designed to evaluate the upper northeast portion of the vein where previous drilling was limited. The reported grades are consistent with previous underground sample data and resource estimates in the vicinity of the drill holes intersections.  We anticipate that we will continue to add or upgrade our resource base as drilling continues in this area."  This phase of surface drilling has been completed and additional drilling will be completed from underground once access has been re-established later this year.

Permitting is well advanced for the mine dewatering and treatment facilities.  A Manager of Mining Activities and a Hydrogeology Engineer have been added to the project team (News Release May 31, 2011).  Their responsibilities will cover all aspects of permitting, inspecting and re-establishing access to the underground workings.

Global commissioned the compilation of existing regional data which is now complete.  Preliminary results are encouraging and as a result, an additional 120 km² of exploration licenses have been applied for.  Initial reconnaissance of newly identified targets will be undertaken during the summer field season.

A mercury spectrometry survey and CSAMT (resistivity) geophysical survey have been commissioned to further examine new exploration areas in close proximity to the Strieborná vein.  The data collected will be used to define and prioritize possible new surface drill targets.

About Strieborná

The Strieborná vein is a high-grade silver-copper-antimony deposit with a defined resource.  The project is part of an historic mining district near the town of Roznava in eastern Slovakia.  The current resource occurs within a mineralized structure 1.2 km long, 600 m deep and an average thickness of 3.4 m.  The resource has been defined by previous drilling and a series of four horizontal underground drifts totaling 3,000 m.  The mineralization is open in various directions along the vein structure.  Other similar structures have been identified within the mining and exploration leases, and these will also be tested for metal potential in subsequent drill programs.

Atomic Emission Spectrometry Shrinks Down For The Field | Latest ...

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Atomic emission spectrometry identifies and measures metals present in a sample by examining the light emitted when the sample is heated. Each element emits a characteristic wavelength of light whose intensity is proportional to the number of atoms in the element.

Unfortunately, typical benchtop instruments are large and immobile and can cost between $75,000 and $100,000, says spectroscopist Bradley Jones of Wake Forest University .

The machine he and his colleagues rigged together cost only $2,500. It weighed just a couple of pounds and fit on a sturdy ceramic base that measured 6 × 30 × 1 cm. The instrument consisted of three components: a small commercial spectrometer, a lens, and a hollow aluminum rod 7.5 cm in height, in which the researchers placed a tungsten wire from a 250 W light bulb.

To test the spectrometer, the investigators analyzed samples of polluted water and of peach and tomato leaves with known amounts of different metals. They pipetted a drop of each sample onto the filament through a tiny hole in the rod. After hooking the instrument up to a car battery, they then passed a current through the filament to heat it up and dry the sample. When the filament began to glow with white light, the metals in the sample gave off their characteristic emissions. The emissions exited the rod through another tiny hole and the lens focused the light into the spectrometer. Jones's team could then inspect the spectra using a laptop computer.

They looked for signals of 15 metals in the samples, including alkaline and transition metals, and could detect all of them. They could clearly pick out metals like chromium and barium that emit light between 400 and 600 nm, but they struggled to find elements like manganese and cesium that emit between 250 and 450 nm. This performance was comparable to that of benchtop instruments "at wavelengths above 400 nm but poorer at lower wavelengths," Jones says.  The portable instrument only needs 20 µL of sample, he points out, compared to the few milliliters necessary for conventional analyses.

Because Jones's instrument could detect cesium and europium, two metals with radioactive isotopes that could appear in "dirty bombs," Jones envisions the instrument's use in homeland security applications. The new instrument has also garnered interest from academic researchers in the developing world where funding for scientific equipment is limited, Jones says.

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