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Dalnegorsk - Nikolaevskoe, Partizansky, Verkhnee, Mayminovskoye, Southern, Silinskoye, Sadovoe, 1st Sovetskoe, Krasnogorskoe, Nizhnee, Monastyrskoye, Smirnovskoye, Akhobinskoye, Lysogorskoye, Dalnee, Sadovoye |
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Primorskiy Kray, Russia |
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Zn Pb Ag B Sn Bi
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Dal'negorsk group of Pb-Zn and Boron skarn-hosted deposits are located ~340 km NE of Vladivostok and ~30 km NW of the port of Rudnaya Pristan on the Sea of Japan coastline. The Pb-Zn orebodies, past and current, include Nikolaevskoe, Partizansky, Verkhnee (Verkhniy), Mayminovskoye, Southern, Silinskoye, Sadovoe, 1st Sovetskoe, Krasnogorskoe, Nizhnee, Monastyrskoye, Smirnovskoye, Akhobinskoye, Lysogorskoye, Dal’nee and Sadovoye. The current Nikolayevskoye, Partizanskoye and Verkhnee deposits are skarn-polymetallic style ores, whereas Mayminovskoye, Southern, Lidovskoe, Krasnogorskoe and Silinskoye are polymetallic vein deposits with a high content of silver. These deposits are located either close to or within a 45 km radius of the Dal'negorsk treatment facility, although Silinskoye is 70 km away. The Dal'negorsk Borosilicate deposit is adjacent to Partizansky in Dal'negorsk (#Location: Dal'negorsk - 44° 33' 5"N, 135° 35' 6"E).
The original mineral claim at Dal'negorsk was pegged in the Tetyukhe (now Rudnaya) river valley in 1897 and named Verkhniy. Further prospecting and test mining was carried out from 1902. Subsequently, full scale mining and processing of polymetallic ores in the Dal'negorsk (then known as Tetyukhe) District began in 1907. Since then, ~20 skarn- and vein polymetallic orebodies have been exploited by both open pit and underground mining in the surrounding district. Between 1911 to 1916 >0.1 Mt of ore were mined from the Verkhniy mine, mainly supergene zinc calamine and smithsonite as direct shipping ore, despatched by sea to England. An enrichment plant constructed in 1912 permitted primary lead and zinc to be extracted, which allowed the operation to expand. Production was paused during the Russian Civil War (Revolution) until new capital was secured in 1924. A lead smelter began operation in 1930 to further process these ores on site. Production has continued to the present (2021) with new mines having been opened and others decommissioned over that period. The current mining and treatment (2020) is ~1 Mt of ore per annum (MMC Dalpolimetall JSC website). The polymetallic operation principally produced Zn and Pb, as well as lesser Sn, Ag, Bi, Cd and In. Tailings have been deposited in two dumps, the first of which contains 7.2 Mt, whilst the second has a capacity of 40 Mt that was half filled in 2012 (Zvereva and Krupskaya, 2013). The Dal’negorsk borosilicate skarn-hosted deposit, which is surrounded by the Pb-Zn deposits, was discovered in 1946 and put into operation in 1959.
The Dal'negorsk deposits are located near the northern extremity of the exposed Taukha accretionary wedge terrane of the Sikhote-Alin Belt, which is, in turn, part of the Pacific Orogen. It is part of the Taukha metallogenic belt of skarn and vein boron and lead-zinc deposits. The Taukha accretionary wedge consists of three imbricated tectonic slices. The slice in the Dal'negorsk district overlies Late Palaeozoic to Jurassic cherts and Triassic to Lower Cretaceous (Berriasian to Valanginian) shelf sandstone and comprises Early Cretaceous (Neocomian) turbidites and olistostromes/melánges. The olistostromes contain allochthonous olistoliths of Late Palaeozoic carbonates and other sedimentary rocks, Mesozoic guyots, Carboniferous-to-Jurassic cherts, Triassic reefal limestone and Triassic and Early Cretaceous (Berriasian to Valanginian) shelf siltstone and sandstone (KItanchuk et al., 1996; Baskina et al., 2009; Seltmann et al., 2010).
This turbidite sequence, including the olistostrome, were deformed into a system of tightly compressed, NE striking linear folds dipping at angles of 30 to 80°, and are overlain by a gently dipping sequence of Upper Cretaceous to Tertiary intermediate to felsic lavas, ignimbrites, volcanic breccias and tuffs that were deposited in graben-like structures and intruded by gabbro-diorite, diorite, granite, rhyolite and dolerite stocks and dykes (Seltmann et al., 2010). This latter suite of volcanic, subvolcanic and intrusive rocks belong to the Late Cretaceous (Turonian to Campanian and Maastrichtian) to Paleogene East Sikhote-Alin Volcanic Belt, representing local volcanic-plutonic centres (Simanenko, 2006). The mineralisation in the Dal'negorsk District is located in a horst that has brought the host turbidite sequence to the surface to be exposed, framed by the younger volcanic edifices.
Significant exposed intrusions are not well developed in the immediate Dal'negorsk area, apart from small granite plugs and basalt/dolerite dykes. The skarn alteration zone in which the borosilicate mineralisation is emplaced, is truncated at a depth of 1000 to 1400 m by a granite-adamellite intrusion. Intrusive contacts of these granitoids have no skarn signatures and cut through grossular-wollastonite skarns, suggesting they post date formation of that borosilicate hosting skarn. The adamellite in this intrusive association is late Paleocene in age, dated at 60.45 ±0.65 Ma (U-Pb; Alenicheva and Sakhno, 2009). This implies the skarn alteration is related to an earlier or different intrusive phase that has been overprinted by the granite-adamellite suite. However, the second/late stage borosilicate mineralisation, interpreted as coeval with the early/first polymetallic mineralisation, does locally intersect the adamellite intrusion to form cross-cutting veinlike bodies. While significant coeval granitoid bodies appear to be absent from the borosilicate deposit area, high-K latite (or ultrapotassic trachyte) dykes and minor irregular subvolcanic intrusions occur among mineralised skarn over an area of 1.8 x 0.9 km within the centre of the borosilicate deposit. These intrusions show evidence of skarn alteration and are spatially associated with orebodies and with suites of intra- and post-mineral basaltic dykes. They are distinguished from basalt and dolerite by their lighter colour and an abundance of porous and amygdaloid varieties with elongated pores parallel to fluidal banding in contact zones. Latite bodies that crop out in the open pit have been traced for 900 m down dip by drilling. Most have been dated between 58 and 57 Ma. The deposition of borosilicate mineralisation is followed by multiple intrusions of sodic basaltic dykes, but no high-K latites. The K-Ar age of postmineral dolerite dykes that cross cut ore-bearing skarn is 55 to 54 Ma (Ratkin et al., 2018; Baskina et al., 2009; Simanenko, 2006).
Despite the difference in ore resources and commodity, the borosilicate and base-metal deposits have much in common in their geology. Both types of mineralisation are localised in horsts of basement, which includes large allochthonous blocks of Triassic limestone that hosts skarn bodies with superimposed mineralisation. Tectonic sheets of cherty- and carbonaceous-clastic rocks make up the basement below the turbidite melánge. The deposits are also related to the intersection of regional faults that control localisation of Mesozoic alkali basalts and Paleogene basaltic dykes. In particular, the borosilicate deposit is situated at the hub-like intersection from which the NNE-trending Partizansky, the near north-south Nikolaevsky, and the NW-trending Pravoberezhny faults radiate (Baskina et al., 2009).
Polymetallic Zinc-Lead Skarn Deposits
Partizansky, one of the more significant polymetallic deposits at Dal'negorsk, has been described as follows by Simanenko (2006). The turbidite-olistostrome complex that hosts mineralisation is composed of clastic sedimentary rocks, mainly a silty matrix containing widely variable sised blocks, clasts and sheets of Lower Cretaceous sandstone, Triassic to Jurassic siltstone, and Middle to Upper Triassic limestone. Individual olistoliths may be as large as 2 to 4 km long and 200 to 800 m thick. Most polymetallic skarn hosted orebodies at Partizansky are localised at the contacts of a large steeply dipping limestone olistolith with siltstone and sandstone of the enclosing turbidite 'matrix'. The position of the orebodies is interpreted to be controlled by faults. Some orebodies are also localised at the contact of the same limestone with unconformably overlying overlying Late Cretaceous volcanic rocks. Orebodies comprise variably dipping veins, lenses and pipelike bodies made up of skarn with sulphide mineralisation. At a depth of between 600 and 800 m below surface, the ore 'pinched-out', grading into almost unaltered limestone, while aluminosilicate rocks are replaced by quartz, sericite and biotite. Mineralisation at Partizansky is distributed over a strike length of ~2 km.
The major ore minerals the Partizansky deposit are sphalerite and galena, with lesser to minor chalcopyrite, arsenopyrite, luzonite, pyrite, marcasite, pyrrhotite, acanthite, tennantite-tetrahedrite, Ag-Pb-Sb and Bi sulphosalts, intermetallic compounds and native elements (allargentum, bismuth, silver, gold), Bi tellurides and sulphotellurides (hedleyite, Se-bearing joseite A), and iron oxides (magnetite, hematite) occur in subordinate and minor amounts.
The ores are medium- to coarse-grained, and have massive, mottled, segregation-disseminated and stringer-disseminated textures. Druses of sulphides associated with calcite, quartz, fluorite and zeolites often fill cavities, interpreted to be the result of hydrothermal karst.
The base-metal skarn hosted mineralisation at Partizansky was deposited in two stages, the:
i). Base-metal stage - in which the bulk of the base-metal mineralisation was deposited as four sequential mineral assemblages in order of deposition:
• Skarn-silicates, forming a skarn zone along fracture systems at the contact of limestone with aluminosilicate rocks. The skarn-silicate assemblage comprises hedenbergite, garnet, ilvaite and axinite, with lesser wollastonite, vesuvianite, fluorite, quartz and calcite. The vertical range of skarn development is ~600 to 700 m, giving way at a depth of ~1 km to slightly greisenised aluminosilicate rocks that are characterised by a topaz, fluorite, muscovite and tourmaline assemblage.
The intensity and diversity of skarn minerals is greatest at the base of the zone, with all of the minerals listed above represented, although hedenbergite dominates and axinite is found close to the contact with clastic rocks. In the middle of the column, hedenbergite is still predominant with subordinate garnet, axinite and quartz, but no ilvaite. In the upper parts of the orebodies, where they pinch out, the silicate skarn minerals are sharply diminished until their complete disappearance, giving way to pre-ore veinlike quartz-calcite metasomatic bodies. Hedenbergite has the highest Fe content in the root zones of the orebodies, gradually decreasing, compensated by an increase in the Mn content from 3 wt.% to 12 wt.% 280 m higher. A similar, but less well defined trend is demonstrated by the variation of Fe and Al contents in garnet, represented by andradite in the lower zone to added grossular in the upper zone.
The absence of both deformation and crosscutting relations between skarn-silicate minerals and younger ore mineral aggregates of this stage, as detailed below, implies they are consecutive mineral assemblages that were derived from a common hydrothermal system. However, the early skarn-silicate assemblage at the Verkhny, Pervy Sovetsky and Nikolaevsky polymetallic deposits also contains ore minerals (Dobrovol'skaya and Balashova, 1993; Mozgova and Borodaev, 1995). These deposits commonly comprise alternating bands of sulphide and silicate minerals. In contrast, the Partizansky deposit shows no such relationship between skarn alteration and sulphides, although some intergranular segregations of Zn and Pb sulphides, chalcopyrite, pyrrhotite and iron oxides may be regarded as coeval with silicate aggregates. It is therefore concluded that, although skarn and ore at the Partizansky deposit were closely related to each other in time, they did not form simultaneously, and most sulphides were superimposed on the skarn alteration.
• Quartz-arsenopyrite, which predated the deposition of significant base-metal mineralisation. Arsenopyrite, associated with quartz, occurs as scattered disseminations or segregations of skeletal and hypidiomorphic crystals both in skarn and in quartz-calcite pre-mineralisation metasomatic rocks in the upper levels of the deposit. The base metal sulphides of the phases below replace this arsenopyrite and fill fissures in its dismembered aggregates, cementing and corroding those fragments. There is a vertical zonation, with its As content decreasing from 47.49 wt.% at the lower levels to 45.65 wt.% at the upper parts of the deposit. Conversely, arsenopyrite in the upper levels is enriched up to 0.24 wt.% Sb.
• Galena-sphalerite was deposited following the brecciation of arsenopyrite, filling fractures and cementing brecciated arsenopyrite grains and aggregates. There is also a vertical zonation of the galena-sphalerite mineralisation (Ratkin et al., 1991; 1994), reflected by variations in mineral composition, with the Pb/Zn ratio increasing upward from 0.1 to 1.
The root zones of the orebodies are largely composed of low-Fe (<2 wt.%) sphalerite, locally up to 95% of this section of the ore zone, occurring as small to massive aggregates within hedenbergite, hedenbergite-ilvaite and hedenbergite-garnet-ilvaite skarn. Other ore minerals, including widespread Bi minerals (Simanenko, 1998) occur as fine disseminations or polymineral segregations in sphalerite. Galena occurs as fine disseminations, veinlets and reticulate aggregates in sphalerite or, more rarely, in aggregates of silicate minerals or sphalerite grains. Galena also occurs in tight intergrowths with Ag-Pb-Bi sulphosalts and is enriched in Ag and Bi, with a variable Bi/Ag ratio. As second generation of AS follows. Tennantyite-tetrahedrite occurs as small monominerallic inclusions in sphalerite or polymineral aggregates intergrown with chalcopyrite, arsenopyrite II, and native Bi.
In the middle of the orebodies, major sphalerite with only slightly lesser galena are accompanied by minor chalcopyrite and tennantyite-tetrahedrite. No significant corrosion textures are observed in galena-sphalerite intergrowths, implying near simultaneous crystallisation. However, embayments of galena in sphalerite suggest the latter precipitated first and continued to be deposited together with galena.
The upper parts of the orebodies are largely composed of galena, which formed later than sphalerite. Sphalerite in the galena-sphalerite mineral assemblage becomes more enriched in Fe content upwards, having progressively increased to ~3.5 wt.% in the middle, to as much as 5 wt.% in the upper zones of orebodies. Galena is depleted in in a number of elements, only containing 0.023 to 0.033 wt.% Ag, 0.048 to 0.060 wt.% Sb, and 0.036 to 0.075 wt.% Bi, in the middle of the orebodies, whilst a combined total of only 0.0008 wt.% of these elements were detected in the upper parts of orebodies. Occasionally, galena contains disseminated tennantyite-tetrahedrite. Minor amounts of chalcopyrite occur as a fine emulsion or microveinlets in sphalerite.
• A pyrite-(pyrrhotite)-marcasite-chalcopyrite assemblage replaces the galena-sphalerite minerals. The Fe disulphides and sulphides and chalcopyrite II are the major minerals. A zonation occurs in which pyrrhotite largely occurs at deeper levels and pyrite and marcasite in the middle and upper parts of the orebodies.
ii). Silver-sulphosalt stage - which postdates local brecciation of base-metal skarn orebodies, but are, in turn, crosscut by mineral aggregates of the second stage. The two stages are also separated from the first stage by the intrusion of basaltic dykes dated at 57 ±5 Ma (Pustov 1990). It is mainly confined to the upper margins of orebodies and pertains to the sulphosalt-galena-chalcopyrite assemblage, that was superimposed on minerals of the first stage.
The silver-bearing assemblages of this second stage are developed on the flanks of the main deposit, largely external to the orebodies, or as cross-cutting veinlets and superimposed aggregates in the uppermost parts of the orebodies. In the latter case, the products of the second stage are spatially juxtaposed with the mineral complex of the first stage.
The silver-sulphosalt stage is well developed at the uppermost level of the Second Contact orebody. It overprints earlier base-metal stage mineralisation with an assemblage of sulphosalts, galena and chalcopyrite, filling fissures and intergranular spaces in aggregates of the early sulphides, and cementing fragments of brecciated base-metal ore. This stage is characterised by abundant disseminations of Ag minerals (pyrargyrite, stephanite, acanthite) in galena II and chalcopyrite III which are the major sulphides. Chalcopyrite III and galena II also contain abundant and finely disseminated freibergite.
NOTE: The Partizansky description is summarised from Simanenko (2006).
The base-metal stage of polymetallic Zn-Pb mineralisation at Partizansky has been interpreted to be coeval with the second stage of skarn development and borosilicate mineralisation in the Dal'negorsk borosilicate deposit, as outlined at the end of the description of the latter deposit below.
Nikolaevskoe - this deposit is also hosted by an olistolith of Triassic limestone (Nokleberg 2010; Nokleberg et al., 1996) occurring as a downthrown block, overlain by Upper Cretaceous rhyolite, volcanic breccias and tuffs, and Paleocene andesite lavas and pyroclastics. All these rocks are intruded by gabbro-diorite, diorite, granite, rhyolite and dolerite stocks and dykes, representing parts of the local volcanic-plutonic centre (Seltmann et al., 2010). The main orebody is flat-lying and tabular, and occupies the uppermost part of the limestone, immediately below the overlying volcanic rocks at a depth of 700 to 1200 m below surface. The mineralisation overprints a pyroxene dominant skarn assemblage with minor garnet and wollastonite and includes galena, sphalerite and pyrrhotite, with minor arsenopyrite, chalcopyrite, magnetite and trace Ag-Bi-Te minerals and cassiterite. Other gangue minerals include ilvaite, axinite, tourmaline, epidote, fluorite, barite and amphibole. The over-lying volcanic rocks carry quartz-sulphide veins, which are associated with silicification and phyllic alteration overprinting more extensive haloes of propylite-like alteration (Seltmann et al., 2010).
Polymetallic Zinc-Lead Vein Deposits
Deposits such as Mayminovskoye, Southern, Krasnogorskoe, Lidovskoe and Silinskoye are polymetallic vein deposits, which only occur in the areas with no allochthonous limestone bodies. Unlike the skarn deposits, the polymetallic vein deposits contain significant tin, mainly as stannite with lesser cassiterite. Some deposits hosted in clastic rocks, are associated with 60 to 65 Ma (K-Ar) granodiorite intrusions. Some ore bodies, as at Lidovskoe deposit, occur in the apices of the intrusions, forming saddle- shaped deposits. The polymetallic vein deposit at Krasnogorskoe is associated with volcanic breccias that are spatially related to a volcanic vent. The breccias also contain disseminated galena, sphalerite, pyrite and cassiterite. This relationship has been interpreted to suggest of these are porphyry tin- polymetallic deposits. The age of hosting volcanic rocks is 60 to 65 Ma (KItanchuk, et al., 1996).
At Mayminovskoye there are ~20 veins that dip at high angles in within an ~500 m thick unit of siltstone and sandstone. Veins carry richer grades sandstones as compared to siltstones. Veins strike NW-SE, with strike lengths of up to 600 m. Mineralisation is developed over a vertical interval of ~400 m, with veins of up to 6 m in thickness, but usually over a range of 2 to 3 m.
At the Southern deposit, the main orebody is Vein 14 with secondary orebodies, Black Vein and Vein 14 Offshoot. These veins are developed from surface at RL 800 to 1000 m to the current operating RL of 440 m, with drilling indicating mineralisation continues to sea level at RL 0. These veins are irregular and anastomosing hosted by a 150 m thickness laminated sandstones. They strike NE-SW for ~800 m and dip at 60 to 70°SE.
The Silinskoye mine is at the process (in 2020) of going underground to retrieve the remaining of zinc-lead-silver mineralisation. In the past it mainly produced tin, zinc and copper. Mineralisation is related to a complex vein which extended from the surface at an RL of 550 m to RL 350 m, striking east-west over an interval of ~50 m and dipping at 70 to 80°S. The average thickness of the vein is ~1 m, hosted in siltstone, and it is composed of quartz carbonates with galenite, sphalerite, cassiterite and chalcopyrite.
The descriptions of these three vein deposits is drawn from the MMC Dalpolimetall JSC website, viewed January, 2021.
Borosilicate Skarn Deposit
The major Dal'negorsk boron skarn deposit is located near the Nikolaevskoe Zn-Pb deposit, hosted by an ~3.5 km long and 600 m thick Upper Triassic limestone olistolith enclosed in terrigenous-cherty rocks (Nokleberg 2010 and references therein). The deposit occurs within a 1 km3 volume of lime-skarn that replaced a steeply dipping limestone layer in the central part of the Dal'negorsk horst. The deposit is limited at a depth of 1000 to 1400 m below the surface by a 60.45 ±0.65 Ma (U-Pb; Alenicheva and Sakhno, 2009) post-mineral granite-adamellite intrusion which post-dated wollastonite-grossular skarn alteration. The principal boron minerals in the deposit is datolite [CaB(SiO4)(OH)] and danburite [CaB2(SiO4)2].
Two periods of skarn alteration are manifested within the deposit (described below after Ratkin et al., 2018):
i). An early stage which produced a large volume of garnet-wollastonite skarn within the host limestone unit. Wollastonite dominates at depth, characterised by low iron and manganese contents of ≤2.0 wt.% MnO and ≤1.0 wt.% Fe2O3. This wollastonite almost completely replaced limestone to form long snow-white aggregates. Garnet associated with the wollastonite averaged 10.0 wt.% Al2O3 and 15.0 wt.% Fe2O3, and during the hydrothermal alteration process, evolved from andradite found in the cores, to grossular on the rims of crystals. In the upper part of the skarn column, hedenbergite is also found, characterised by high MnO contents of as much as 8 to 10 wt.%.
Above the grossular-wollastonite skarns, at a depth of 500 to 600 m below the palaeo-surface, a zone of hydrothermal karst was formed, occurring as abundant pipe-like branching cavities within limestone. The sizes of these cavities in plan were as much as several tens of metres across. Precipitation of mineral aggregates from mineralising hydrothermal fluids gradually filled these cavities. Their walls were initially covered with banded datolite-wollastonite-ferrosilite-hedenbergite mineral geodes (Ratkin et al., 1993). These banded mineral aggregates also contained light-colored bustamite layers. Crown-shaped danburite druse also formed in these geodes with perfectly faced crystals ranging from 1 to 2, to 100 cm across. At the close of the hydrothermal process, parts of the cavities was filled with quartz-calcite aggregates. Post-mineral basaltic melt dated at 78 Ma (K-Ar; Dubinina et al., 2011) was injected into unfilled cavities to form rare nodules.
i). Late superposed stage which overprint the early mineral assemblages, including danburite clusters. Dating of orthoclase alteration (39Ar/40Ar; Leier and Ratkin, 1997), show late skarn was formed in the Late Paleogene (57.24 Ma), synchronously with the formation of skarn-polymetallic orebodies in the adjacent Partizanskoe Pb-Zn deposit which is described above (Ratkin, 1995; Simonenko and Ratkin, 2008). During this stage, early wollastonite, garnet and hedenbergite were preserved, with late garnet-hedenbergite aggregates occurring as parts of veinlets crossing thinly bedded datolite-wollastonite-hedenbergite geodes and early wollastonite-grossular skarns. Danburite was not preserved anywhere, except from the marginal northeastern part of the deposit where it was largely altered to quartz-calcite aggregates in which the primary danburite is only recognised locally from skeletal forms of crystals. However, polyminerallic pseudomorphs formed where danburite was enclosed by basalt. These pseudomorphs preserved both the shape and striation on the faces of the original crystals. Zonal pseudomorphs, from margin to centre, comprised orthoclase, axinite, andradite, hedenbergite, datolite, quartz and calcite (Khetchikov et al., 1991). Gaseous and liquid inclusions in pseudomorph minerals show they formed in the temperature range of 350 to 120°C. The late early stage basaltic cavity fill underwent hydrothermal reworking simultaneously with the early danburite, with orthoclase replacing basaltic microlites, as well as quartz after albitised plagioclase and hedenbergite after orthoclase (Ratkin et al., 2018).
Seltmann et al. (2010) suggest this late stage represents an overprinting retro-grade hydrosilicate assemblages containing quartz, calcite, B-bearing minerals (datolite, danburite, axinite, ilvaite), epidote, chlorite, albite, sericite and various sulphides. They describe the ores as having massive, spotty, banded, brecciated and especially notable concentric textures. The latter is caused by rhythmically alternating bands of wollastonite, pyroxene, garnet, datolite and other minerals. Datolite is the most abundant boron mineral in the deposit, mostly on the upper levels, where it forms monomineralic lenses and patches. At greater depths, datolite forms thin-banded aggregations together with pyroxene and wollastonite.
Late skarn alteration intersects the adamellite intrusion in the form of cross-cutting veinlike bodies, although the intrusion itself truncates the main Dal'negorsk borosilicate deposit at depth. Both granites and vein-like skarn bodies in granites are crosscut by Early Eocene 56 to 55 Ma (K-Ar) basaltic dykes without any signs of hydrothermal reworking (Ratkin et al., 2018).
The temporal and spatial association between the borosilicate and polymetallic Zn-Pb deposits of the Dal'negorsk district is illustrated by the relationship between the Dal'negorsk borosilicate and Partizansky Zn-Pb deposits which are close neighbours, as described by Ratkin et al. (2018). The Partizanskoe deposit has a vertical mineralogical and geochemical zonation from a root zone at depth, characterised by an assemblage of ilvaite-andradite-hedenbergite skarns with weak sulphide development and mathildogalenite (Ag-Bi-galenite), which passes upward into hedenbergite skarns and quartz-calcite metasomatic rocks with galenite and sphalerite (Simanenko and Ratkin, 2008). Observations suggest the zone of late stage skarn development at the Dalnegorsk borosilicate deposit is a direct continuation of skarn zones on the northeastern flank of the Partizanskoe Pb-Zn deposit, i.e., the zone of early grossular-wollastonite skarns and the zone of hydrothermal karst with danburite of the Dalnegorsk borosilicate deposit is a direct continuation of the late ilvaite-andradite-hedenbergite skarns with mathildogalenite in the root facies of skarn-polymetallic ores at the Partizanskoe deposit. Ratkin et al. (2018) interprete the two to have identical mineralogical and geochemical characteristics. In both cases, hedenbergite is strongly ferruginous, with low Mg and Mn contents. Garnet in late skarns have average Al2O3 and Fe2O3 contents of ~3.0 and 25.0 wt.%, respectively. Similarly, as garnet crystals of the Partizanskoe Pb-Zn deposit are characterised by a zonal structure from an andradite core to a grossular margin. Ilvaite is also identical. Data also shows the isotope composition of lead in galenite from mineral aggregates of the Dalnegorsk borosilicate deposit is nearly identical to galenite from Pb-Zn ores of the Partizanskoe deposit. The only perceived difference between late skarns of the Dalnegorsk deposit and early skarns of the Partizanskoe deposit is the abundance of datolite in the former.
Conclusions Prograde skarn alteration was the first event in the district, followed by overprinting borosilicate mineralisation which formed a core surrounded by the overlapping, younger polymetallic Zn-Pb skarn ores. Where carbonate country rocks are absent, skarn alteration is not developed and polymetallic Zn-Pb was deposited as veins with tin and silver.
Reserves and Resources
The 'ore reserves' of the Dal'negorsk borosilicate deposit are estimated at 300 to 350 Mt (35 to 40 Mt of B2O3) comprising 200 Mt of indicated and 132 Mt of inferred reserves in the C1 and C2 categories in the Russian reserve classification (Baskina et al., 2009). This would equate to grades of ~11.5% B2O3.
Remaining published Russian Reserve Classification reserves estimates for the Dal'negorsk polymetallic Pb-Zn deposits, after 114 years of mining, include (MMC Dalpolimetall JSC website, viewed January, 2021):
• Nikolayevskoye - 8.453 Mt of C1 category reserves, in an underground mine;
• Partizanskoye - 4.026 Mt of B+C1 category reserves, in an underground mine;
• Verkhnee - 1.285 Mt of C1 and 0.59 Mt of off-balance C1 category reserves, in an open pit mine;
• Mayminovskoye - 0.279 Mt of C1 category reserves, in an underground mine;
• Southern - 0.301 Mt of B+C1 category reserves, in an underground mine;
The total B+C1+C2 reserves for these deposits - 16.404 Mt @ 4.1% Zn. 2.69% Pb, 68 g/t Ag.
Past production has resulted in the treatment of 58 Mt of ore.
The most recent source geological information used to prepare this decription was dated: 2018.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Dalnegorsk
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Baskina, V.A., Prokofev, V.Yu., Lebedev, V.A., Borisovsky, S.E., Dobrovolskaya, M.G., Yakushev, A.I. and Gorbacheva, S.A., 2009 - The Dalnegorsk Borosilicate Skarn Deposit, Primorye, Russia: Composition of Ore-Bearing Solutions and Boron Sources: in Geology of Ore Deposits (Pleiades Publishing) v.51, pp. 179-196.
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KItanchuk, A.I., Ratkin, V.V., Ryazantseva, M.D., Golozubov, V.V. and Gonokhova, N.G., 1996 - Geology and mineral deposits of Primorsky Krai - Excerpt: in The Taukha metallogenic belt of skarn and vein boron and lead-zinc deposits, Russian Accademy of Science, Far East Geological Institute, Primorye Exploration and Mapping Expedition, Vladivostok, pp. 26-28.
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Ratkin, V.V., Eliseeva, O.A., Pandian, M.S., Orekhov, A.A., Mohapatra, M. and Vishnu Priya, S.K., 2018 - Stages and Formation Conditions of Productive Mineral Associations of the Dalnegorsk Borosilicate Deposit, Sikhote Alin: in Geology of Ore Deposits (Pleiades Publishing) v.60, pp. 1-13.
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Seltmann, R., Soloviev, R., Shatov, V., Pirajno, F., Naumov, E. and Cherkasov, S., 2010 - Metallogeny of Siberia: tectonic, geologic and metallogenic settings of selected significant deposits: in Australian J. of Earth Sciences v.57, pp. 655-706.
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Simanenko, L.F., 2006 - Partizansky Base-Metal Skarn Deposit, Dalnegorsk Ore District, Russia: Stages of Ore Formation, Mineral Assemblages, and Typomorphism of Fahlore: in Geology of Ore Deposits (Pleiades Publishing) v.48 pp. 290-303.
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