The Altai Mountains (called ‘Altay Shan’ in Chinese) is a complex Central Asian mountain system extending some 1,200 miles (2,000 kilometers) in a southeast-northwest direction from the Gobi Desert to the western Siberian plain through parts of China, Mongolia, Russia, and Kazakhstan; with its jagged mountain ridges deriving their name from the Turkic-Mongolian ‘altan’, - meaning “golden.”
Although formed during the great orogenic (mountain-building) upthrusts that transpired between 500 and 300 million years ago, the Altai have since been worn down, turning this part of Kazakhstan into a gently undulating plateau.
Over the course of geologic time, extreme dislocations suffered by the Altai have occasioned a variety of rock types, many altered by magmatic and volcanic activity; resulting in large accumulations of geologically young, unconsolidated sediments in numerous intermontane depressions where tectonic structures bear commercially exploitable deposits of minerals, - such as gold (‘altan’).
The “Central Asia-Chinese Altay Shan Gold Belt” (in which Alhambra operates) is one component of the great Central Asian Orogenic Belt (also known as the Altaid), shaped by a complex geological history; where ore-forming processes (‘creating’ many world-class deposits) transpired within the context of large-scale geodynamic events of plate and plume tectonics (e.g., assembly/breakup of supercontinents).
Here, a complex cycle of rifting, subduction, accretion and collision culminated in the ‘present’ complex assembly. Major mineral deposits distributed across central Eurasia were formed during a range of magmatic episodes from the Ordovician to the Jurassic in connection with magmatic arcs within the extensive subduction-accretion complex, with large ore deposits sourced from the Earth’s crust (… some associated fluids also reveal a mantle component).
As currently cast, Kazakhstan is composed of several microcontinents and island arcs having distinctly different geological histories; for numerous terranes (episodes of terrane amalgamation and accretion) were welded together in an oceanic setting, with the principal terranes in Kazakhstan amalgamated between Early Ordovician and Late Silurian times.
Fortunately, this region’s late Paleozoic-early Mesozoic tectonic evolution provided a very favorable geological setting for the formation of gold deposits (along sutures between the major Eastern Asia cratonic blocks), including Alhambra’s Altay Shan, where Orogenic gold deposits are known to be very widespread. In fact, within its unique geologic setting (the Northern Kazakhstan Metallogenic Province), numerous world-class gold deposits are hosted, with pay zones within these immense gold fields ‘resembling’ those found at Uzboy, Dombraly and Shirotnaia in every way, except that they are ‘just’ much larger (in topographic extent); which is why recent activity at all three of Alhambra’s advanced projects is extremely promising.
Excellent drilling results (at all three of Alhambra’s major projects) are setting the stage, during 2012, for aggressive expansion/delineation of ‘gold occurrence’ mineralization along strike into various ‘high-potential probability’ intervals as follow-up drilling couples with spatial and statistical geochemical analysis to begin the process of ‘corridor mapping’, - integrating geological data, structural information, and geographic (lat/long) coordinates to un-conceal the composition and structure of new ‘gold-bearing vein resource deposit clusters’.
And, as always, large gold fields will grow over time and space hand in hand with additional drilling that delineates their potential; with this elemental ‘strategy’ being pursued (at Uzboy, Dombraly and Shirotnaia) to increase mineralization; steadily enlarging along strike and depth.
As a first step toward fixing a vast inventory of potential mineral targets into a single comprehensive regional framework, Alhambra is interpreting gravity and magnetic geophysical surveys coupled with a remote sensing survey; elucidating satellite imagery; interpreting geological information from diverse spectral intervals; sharply illuminating the subsurface southeastern flank of its license area.
By year-end 2011, Alhambra should obtain an improved understanding into this, its very own, rapidly emerging ‘significant gold trend’, - at least 50 auspicious kilometers of potential (where it is looking forward to identifing some new ‘primary targets’).
Why such excitement?
Because, - located centrally between Shirotnaia and Dombraly is an unusually ‘exceptional’ sliver of the Northern Kazakhstan Metallogenic Province, a propitious ‘point of convergence’ wherein a Middle Ordovician volcano-sediment sequence (truncated by Late Ordovician to Devonian intrusions) hosts numerous gold deposits.
Here, where mineralization of the volcano-sediment hosted Orogenic style is defined by anticline-syncline inflexions and fluid barriers (formed by volcanic rocks covering sediments), tectonic evolution provided a favorable geological setting for the formation of lode gold deposits.
It is here, innermost to this extensive trend (the great Central Asian orogenic belt’s Altaid orogenic collage), that Alhambra’s North Balusty, Dombraly, Kerbay, and Shirotnaia zones of gold mineralization reside.
Shirotnaia enjoys an enormous exploration ‘target area’ of 10 kilometers by 2 kilometers, where a Middle Ordovician volcano-sediment sequence, truncated by Late Ordovician to Devonian intrusions, underlies the prospect. Attendant mineralization belonging to the volcano-sediment hosted Orogenic style is related to the anticline-syncline inflexion line, with fluid barriers formed by volcanic rocks covering sediments.
Locally, Shirotnaia and the massive world-class Aksu/Quartzite Hills orogenic gold deposits are within the same major flexure of the “Aksu-Balusti Mineral Trend”; where, throughout, gold deposits are genetically and spatially related to granite-like rocks; with the larger gold deposits closely linked to intrusions characterized by multi-stage, complex activity. Intrusion formation reflects various structures and ages, with small intrusions and dykes lying inside them.
At both of these favorable locations, gold deposits are found along a trend of deep seated lineaments (orientated within the Stepnyak and Selentinsky synclines) that is comprised mainly of Ordovician sediments; with major gold deposits situated within Late-Ordovician or Silurian low-normal-sulphur gold-quartz veins.
Gold is derived from ancient Pre-Cambrian rocks, with deposit size depending primarily on the intensity of Caledonian intrusive activity, for structure is fundamentally the most important factor in gold deposit formation.
All in all, these gold deposits are to be found in clusters within the most complex structures, - where tectonic activity has formed large and deep breaks/faults, schistosity zones, and areas of faulting tectonics of pre-intrusion and ore stages. Also, with gold deposits chiefly situated close to prominent horst and graben structures, among the pre-Cambrian and Palaeozoic basement, the deeper one drills, the better results will tend to be.
Just such a ‘favorable environment’ was ‘disclosed’ at Shirotnaia.
Look at this: 136 mineralized intervals of variable widths (gold grades greater than 0.2 g/t) were intersected in 42 of 46 holes drilled; resulting in 65 mineralized intervals (of variable widths) containing an average gold grade greater than or equal to 1.0 g/t Au.
Importantly, drill results demonstrated higher-grade intercepts distributed consistently along the main structure, a very large area of mineralization; with high-grade mineralization intersected including 17.15 g/t Au over 3.0 m, 4.83 g/t Au over 9.0 m and 4.15 g/t Au over 7.0 m.
As outlined by diamond drilling, the area of gold mineralization has been extended approximately 600 m to the NE and 200 m to the SW; covering an area measuring 1,800 m by 750 m; still open to the NE and SW along strike, as well as to the N.
A very large area of mineralization has been discovered. Indeed.
Remaining open in three directions and at depth bodes exceedingly well for the future since, as just noted, in this particular environs, ‘the deeper one drills, the better results will tend to be’.
There are now five zones, all of which ‘get better’ with depth, and all of which are currently open at depth,-
• Zone #1 (Main Zone) was extended approximately 200 m along strike to the SW, in the direction of the Western Zone (Zone #3). The best mineralized interval from the 2011 drilling program in this zone was in DDH 03-02 that returned 28.00 m @ 1.19 g/t Au (including 3.00 m @ 5.24 g/t Au) and 13.00 m @ 2.33 g/t Au (including 7.00 m @ 4.11 g/t Au).
• Zone #2 (Southern Zone) was intersected in DDH 32-02, extending 120 m along strike and 55 m along dip. At depth, this zone splits into two wider zones. DDH 28-07 intersected mineralized intervals of 31.50 m @ 1.35 g/t Au (including 12.60 m @ 2.77 g/t Au) and 20.40 m @ 1.02 g/t Au. It is thought that the strike length of this zone could reach at least 350 m, remaining open to the SW.
• Zone #3 (Western Zone) has already been expanded by 200 m in this direction, and, if further drilling demonstrates that the gold mineralization continues between the Western Zone and the Main Zone (Zone #1), then Shirotnaia’s ‘total’ mineralized area will reach 2,600 m by 750 m; thereby increasing the area of known mineralization by 44%.
• Zone #4 (Northern Zone) has a higher-grade part of the zone, running at least 500 m along strike and 75 m down dip, having a width of 4.0 m to 18.0 m; and DDH 96-01 demonstrates that the zone becomes wider at depth. The two best mineralized intervals in this hole are 18.00 m @ 1.10 g/t Au and 8.00 m @ 2.01 g/t Au. Meanwhile, the northern flank of this zone remains underexplored.
• Zone #5 (Central Zone) is where DDH 100-02 (in 2010) intersected higher-grade mineralization at depth (36.0 m @ 4.32 g/t Au). The 2011 drill program proved that the length of the higher-grade part of the zone is approximately 550 m along strike and at least 115 m down dip; with its width varying from 3.0 m to 14.0 m. This mineralization zone consists of at least two segments, as its higher-grade part becomes wider at depth. The zone returned several higher-grade intercepts, the best of which are 14.00 m @ 1.10 g/t Au in DDH 52-02, 9.00 m @ 4.83 g/t Au in DDH 80-03 and 7.00 m @ 4.15 g/t Au in DDH 96-03.
• Similar to Zone #4, Zone #5 continues to the NE as low-grade gold mineralization containing narrow (1.0 m to 3.0 m wide) but higher-grade (up to 1.29 g/t Au) gold mineralization another 550 m to the E; remaining open in this direction.
When you examine a visual map of Shirotnaia that plots the results of this extensive drilling activity, everywhere there are solid ‘hits’, where dozens (almost too many to count) core hole positions have turned up positive results.
As the old saying goes, "Thar's Gold in Them Thar Hills".
During 2012, focus can now be shifted to closer-spaced ‘infill drilling’ to fully delineate the dimensions and scope of these new zones, whose potential is as of yet still unknown, but could be just ‘the tip of the iceberg’.
Also, consider that the average depth of these holes was a mere 139 m, while, at Uzboy, ‘deep holes’ ranged in depth from 520 m to 700 m.
Just imagine what ‘deep drilling’ at Shirotnaia will reveal. After all, the probable continuation of the high grades to depth is usual for this style of mineralization. Moreover, within this gold belt, there are typically large very-high-grade ‘deep’ gold deposits.
In conclusion:
From at least 3.5 billion years ago, the distribution of mineral deposits has been shaped by the geological processes which has formed them, - with such deposits commonly clustered in geological provinces, such as the one where Alhambra now operates.
For economic quantities to be present, the source fluids and metals within a mineral system must be able to migrate in a focused way (‘main fluid pathways’) to a site of deposition, where they subsequently become ‘contained’ by the main regional control (‘trap’).
In general, mineral deposits exhibit extremely heterogeneous distributions, with each major deposit type showing a distinctive (typically unique) temporal pattern; with these individual temporal patterns reflecting a complex interplay between fundamental forces of formation and forces of preservation that (in turn) have largely been shaped by changing tectonic processes and environmental conditions.
As such, the temporal distribution of gold deposits will reflect the forces that originally produced the deposits (global heat flows in a cooling Earth), the depositional environments in which they formed (changes in tectonic regime), and, finally, the preservation potential of the deposit-hosting environments (where such deposits currently reside).
In this context, metallogenic belts and provinces will be dominated by deposits formed in one or more favored epochs, - and nearly twenty large (many world-class) gold deposits have already been disclosed in Kazakhstan, in addition to hundreds of small and medium-sized occurrences.
Globally, most (if not all) metal accumulations of exceptional size are “the end of the spectrum” of decreasing size deposits of the same or similar types; where the 80/20 rule generally prevails, meaning that 20% of the largest deposits contain 80% of the total gold.
To narrow the focus: within the metallogenic province of northern Kazakhstan, major gold deposits are located along a trend of deep seated lineaments (orientated within synclinal zones) composed mainly of Ordovician sediments.
And, yes. Alhambra’s North Balusty, Dombraly, Kerbay, and Shirotnaia zones are all located along the same ‘structure’ of volcano-sediment hosted Orogenic style mineralization; a very distinctive temporal pattern that also hosts the world-class Aksu/Quartzite Hills gold deposits.
At every one of these sites, gold deposits are found in effusive-sedimentary Ordovician masses; where the gold deposits are genetically and spatially in granite-like rocks; with the larger gold deposits related to intrusions characterized by multi-stage complex activity; with intrusion formation made up of various structures and ages.
Within this ‘prolific trend’, Kerbay is positioned between Dombraly (30 kilometers to the North) and Shirotnaia (15 kilometers to the SouthWest), with Dombraly located just 7 kilometers south of North Balusty.