Zinc is the fourth most consumed metal globally and its corrosion resistance properties contribute significantly to the longevity, reliability, and sustainability of construction and infrastructure projects, vehicle manufacturing, and green technologies. By extending the lifespan of these assets and promoting durability, zinc supports the goals of the green transition by reducing resource consumption, minimizing waste, and enhancing overall environmental performance. Four broad ore deposit types account for over 90% of global zinc production and known resources. These are, in order of importance, shale-hosted massive sulphide (‘VHMS’) deposits, volcanogenic massive sulphide (‘VMS’) deposits, carbonate replacement (‘CRD’) deposits, and Irish-type / Mississippi-valley type (‘IT’ / ‘MVT’) deposits. Each ore deposit type contains a relatively small number of world-class ore deposits which are characterized by their large size, high-grades, and economic viability. These world class deposits represent the most significant de-posits within their respective deposit types and generally attract substantial attention and investment from mining and exploration companies. The Irish Midlands basin is a globally significant area for zinc exploration and mining and discoveries over the past 60 years have demonstrated its potential to generate world-class deposits. One notable example is the Navan de-posit, which is one of the largest known Irish-Type/Mississippi Valley-Type (IT / MVT) deposits in the world. Navan has been a prolific producer of zinc and lead ores for the past 45 years, contributing significantly to the mineral wealth and economic development of the region. Irish-type deposits, such as Navan and Lisheen/Galmoy, have the advantage of being metallurgically straightforward and of producing clean concentrates with minimal impurities. Such clean concentrates are highly sought after by zinc smelters worldwide, as they allow for efficient blending with other zinc concentrates of lower quality. After decades of mineral exploration, the potential for new discoveries in the Irish Midlands basin still remains high. The metal endowment of the basin and quality of its deposits, coupled with advances in exploration technologies, such as seismics, make it an attractive exploration play. Large areas of the basin also remain relatively underexplored, particularly under cover rock sequences, such as the Tober Colleen Formation (the lowermost part of the “Calp”). Indeed, the combination of accumulated geological knowledge, technological advancements, and on-going exploration programmes greatly enhances the likelihood of new and exciting mineral discoveries in the Irish Midlands basin in the coming years. In summary, the Irish Midlands basin's track record of discoveries and the characteristics of Irish-type deposits, including their size, grade and concentrate quality, reinforce the basin's significance in global zinc exploration and mining. Production of zinc from the Irish Midlands basin also contributes to the European Union’s (EU) mineral self-sufficiency objectives and sustainability agenda thereby enhancing resource security, reducing carbon emissions, and fostering a more sustainable and resilient mineral supply chain within the EU.

Porphyry deposits supply the bulk of the world's Cu and Mo and significant amounts of Au, as well as other minor and trace metal(loid)s, including Ag, Re, Te, Pd, Se, Bi, Zn, and Pb. Porphyry deposits are gaining in importance as a source of critical raw materials with the increasing global demand for these commodities. To date, minor and trace metal(loid)s are still commonly recovered as by-products from porphyry ores with-out prior characterization of their host mineralogy that could inform more efficient processing and improved recoveries. We report a comprehensive metal(loid) deportment study on a complete vein paragenetic series in samples from the northwestern high-grade zone of the Bingham Canyon Cu-Mo-Au porphyry deposit, Utah. The polyphase Bingham stock comprises an early premineralization equigranular monzonite phase that was intruded by a series of five successive, ore-related porphyry intrusions. Veins with hypogene Cu-(Fe) sulfide assemblages from all five porphyry intrusions were characterized for their trace metal(loid) contents by laser ablation-inductively coupled-mass spectrometry (LA-ICP-MS).It was found that bornite and digenite contain elevated Bi, Ag, Te, and Se relative to chalcopyrite, whereas the latter contains elevated concentrations of Co, Ga, and In. A stepwise decline in sulfide abundance occurs over the porphyry intrusion sequence and is more pronounced in digenite and bornite than in chalcopyrite. The related diminishing concentration per rock volume (inventory) of Bi, Ag, Te, and Se in the youngest porphyry dikes could have been caused in part by a geochemical change in the mineralizing fluid supply across successive intrusive-hydrothermal cycles.Element mapping of exsolved digenite within bornite revealed characterstic partitioning of metal(loid)s between bornite and digenite; most notably Ag, but also Te and Au are enriched in digenite relative to enclos-ing bornite. Bornite domains within these composite grains reveal complex zonation of Sn, In, and Bi, which are attributed to stress-induced diffusion within bornite, resulting from the digenite exsolution process. The selective partitioning of metal(loid)s between bornite and digenite is likely a common feature in many porphyry Cu deposits, given the fundamental mineralogical characteristics of these two sulfides. Our results contribute to an improved understanding of the distribution (from mineral to deposit scale) of critical trace metal(loid)s in porphyry deposits, particularly those containing exsolved digenite. This knowledge can be applied to determine more accurately the value of ore resources, to improve geometallurgical models and by-product recoveries, and to help limit the environmental effects of metal(loid) dispersion.

Five separate porphyry intrusions have been mapped on the basis of crosscutting relations between dikes and veins. Each intrusion was followed by a cycle of quartz vein formation, potassic alteration and copper-gold deposition. The first porphyry is coeval with the bulk of the copper-gold ore in the deposit, and metal introduction decreased through later cycles. Deposition of bornite-digenite-chalcopyrite and gold occurred relatively late within each porphyry cycle, after the main stage of quartz vein formation at 400 to >575°C. Cathodoluminescence petrography shows that copper-iron sulfides, minor quartz, and minor K-feldspar were deposited in fractures and irregular vugs within early formed quartz veins and wallrock, and preliminary fluid inclusion data indicates that sulfide deposition occurred at temperatures below 400°C. Fluid inclusions in quartz veins spanning a 1500m vertical range show that initially homogeneous CO2-rich magmatic-hydrothermal fluids underwent phase separation within the porphyry conduit at estimated paleodepths of 2-3 km. Molybdenite-quartz veins formed after termination of dike emplacement, and are in turn cut and offset by quartz-sericite-pyrite veins.

The Bingham Canyon porphyry copper-gold-molybdenum deposit is one of the largest and highest-grade porphyry orebodies in the world. This study focused on the northwest side of the deposit where quartz mon-zonite porphyry (QMP), the first and largest porphyry intrusion, hosts the bulk of the high-grade copper-gold ore (>1.0% Cu, >1.0 ppm Au). The north-northeast–trending, high-grade zone had pre-mining dimensions of 1,500 m strike, >300 m vertical, and 500 m width and contained more than 500 million tonnes (Mt) of ore associated with potassic alteration and abundant quartz veins. The lack of superimposed sericitic alteration yielded ideal exposures in which to study the early, high-temperature stages of ore formation, a style of mineralization that in many porphyry deposits represents the major period of copper introduction. We mapped multiple porphyry dikes in the sequence: (1) QMP, (2) latite porphyry (LP), (3) biotite porphyry (BP), (4) quartz latite porphyry breccia (QLPbx), and (5) quartz latite porphyry (QLP). Porphyry dikes, faults, and quartz veins are steeply dipping and have two dominant orientations; north-northeast– and northwest-striking. Dikes have a north-northeast strike but they thicken and develop northwest-trending apophyses and host high-grade copper-gold zones at intersections with northwest-faults, indicating that magmatic-hydrothermal fluids were focused by these structural intersections. Each porphyry intrusion was accompanied by a similar sequence of veins, potassic alteration, and sulfides. Biotite veinlets were followed by fractures with early dark micaceous (EDM) halos of sericite, K-feldspar, biotite, andalusite, and local corundum containing disseminated bornite-chalcopyrite-gold. EDM halos are cut by multiple generations of A-quartz veins representing the main Cu-Au ore-forming event. Postdating all intrusions are quartz-molybdenite veins followed by quartz-sericite-pyrite veins. Cathodoluminescence (CL) petrography identified distinct A-quartz veinlets consisting of dark-luminescing quartz filling fractures and dissolution vugs in earlier A-quartz veins and adjacent porphyry wall rock. These veinlets contain abundant bornite and chalcopyrite and minor K-feldspar and are closely linked in time to the introduction of the bulk of the copper and gold. Although a similar sequence of veins was repeated on emplacement of all porphyry intrusions, the vein density and intensity of potassic alteration declined with time. The youngest porphyry, QLP, is mostly weakly mineralized and locally unaltered. These observations indicate that magmatic-hydrothermal fluids underwent a similar physiochemical evolution during and immediately following emplacement of each of several porphyry dikes. The relationship between EDM veins and A-quartz veins requires that the flux of magmatic fluid from the magma chamber occurred in an episodic manner as opposed to a continuous discharge. Vein truncation relationships coupled with abrupt changes in copper-gold grades, sulfide ratios, and potassic alteration intensity at porphyry intrusive contacts indicate that the mass of introduced copper and gold decreased significantly during successive porphyry intrusive-hydrothermal cycles, presumably due to depletion of metals and volatiles in the underlying magma chamber.

Fluid inclusion microthermometry and laser-ablation ICPMS microanalysis are combined with geological and textural observations to reconstruct the spatial and temporal evolution of magmatic fluids that formed the subvolcanic porphyry Cu-Au(-Mo) ore deposit at Bingham Canyon, Utah. The Bingham Canyon orebody is exposed over similar to 1.6 km vertically and has the shape of to inverted cop with distinct metal zoning.Fluid inclusions in the barren but highly veined and potassically altered deep center of the system have intermediate density (similar to 0.6 g cm(-3)) and a salinity of similar to 7 wt percent NaCl equiv. They have subequal concentrations of Na, K, Fe, Cu and contain minor CO2. The intermediate-density fluids were trapped as a single phase, mostly at >500 degrees C and >800 bars. The Au-Cu-rich center near the top of the orebody contains low-density vapor inclusions (similar to 0.2 g cm(-3)) coexisting with brine inclusions containing similar to 45 wt. percent NaCl equiv. The vertical transition Of different inclusion types indicates phase separation of the single-phase input fluid upon volume expansion associated with a pressure drop to 200 +/- 100 liars. Mass-balance calculation based on all analyzed inclusion components indicates that the mass of the vapor phase exceeded that of the brine by similar to 9/1. The vapor contained Cu as its dominant cation (similar to 1.5 wt%) and contributed about 9.5 percent of the total amount of copper transported to the base of the orebody. Bornite. chalcopyrite, and native gold were precipitated in a narrow temperature interval from 430 degrees to 350 degrees C, into secondary pore space created by local redissolution of vein quartz as a result id quartz solubility in the vapor-dominated fluid system.Intermediate-density fluid inclusions in the deepest parts of the peripheral copper ore zone have identical density and composition, including similar gold contents, as those in the deep center. Microthermometry and statistical estimation of phase proportions in the inclusions show that the vapor in the peripheral Cu-rich but Au-poor ore zone remained denser, and the separating brine was less saline (similar to 36 wt% NaCl equiv), compared to vapor and brine in the central Au-Cu ore zone. This indicates that the peripheral fluids experienced a lower degree of phase separation, due to slightly higher fluid pressure at equivalent temperature, compared to more strongly expanding fluids in the center oldie system.The systematic zoning or Au/Cu within the ore shell, despite compositionally similar input Hinds. is interpreted to have resulted from slightly different pressure-temperature-density evolution paths of magmatic fluids. Copper was selectively precipitated in the peripheral ore zone, in contrast to complete coprecipitation of Au and Cu ill the central upflow zone of the vapor plume. The formation of particularly rich Cu-Au ore in the center of the upward-expanding fluid plume is consistent with published experimental data, showing that the solubility metals in hydrous vapor decreases sharply with falling pressure. due to destabilization of the hydration shell around metal complexes in expanding vapor. This interpretation supports the classic vapor plume model for porphyry clipper ore formation but additionally emphasizes the role of sulfur-bearing complexes as a key chemical control on magmatic-hydrothermal Metal transport and the deposition of Cu and Au in porphyry ores. Our interpretation of selective Cu +/- Au precipitation as a function of vapor density can explain die more general observation that most gold-rich porphyry copper deposits;tie formed in shallow sub-volcanic environments. whereas deeper scated porphyry Cu-(Mo) deposits are generally gold poor.

Scanning electron microscope cathodoluminescence imaging is used to map successive generations of fluid inclusions in texturally complex quartz veinlets representing the main stage of ore metal introduction into the porphyry Cu–Au–Mo deposit at Bingham, Utah. Following conventional fluid inclusion microthermometry, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICPMS) is applied to quantify copper and other major and trace-element concentrations in the evolving fluid, with the aim of identifying the ore-forming processes.

Quartz veins in porphyry copper deposits record the physiochemical evolution of fluids in subvolcanic magmatic-hydrothermal systems. We have combined cathodoluminescence (CL) petrography with fluid-inclusion microthermometry to unravel the growth history of individual quartz veins and to link this history to copper ore formation at Bingham, Utah. Early barren quartz veins with K-feldspar + biotite (potassic) alteration selvages occur throughout the 2 km vertical exposure of quartz monzonite porphyry stock. At depths of 500 m to at least 1350 m below the orebody, fluid inclusions in these barren veins trapped a single-phase CO2-bearing fluid containing similar to2-12 wt% NaClequiv. Within and to depths of 500 m below the orebody, early quartz veins contain abundant hypersaline liquid (38-50 wt% NaClequiv) and vapor-rich inclusions trapped together at temperatures of 560-350 degreesC and pressures of 550-140 bar, consistent with fluctuations between lithostatic and hydrostatic pressure at paleodepths of 1.4 to 2.1 km. CL petrography shows that bornite and chalcopyrite were deposited together with a later generation of quartz and K-feldspar in microscopic fractures and dissolution vugs in early barren quartz veins and wall rock. This late quartz contains hypersaline liquid (36-46 wt% NaClequiv) and vapor-rich inclusions trapped at 380-330 degreesC and at 160-120 bar hydrostatic pressure. We conclude that a single-phase magmatic-hydrothermal fluid underwent phase separation to hypersaline liquid (or brine) and vapor similar to500 m below the base of the orebody at a paleodepth of similar to2.5 km. Brine and vapor continued to ascend and formed multiple generations of barren quartz veins with potassic selvages. Thermal decline to temperatures below 400 degreesC was the main driving force for copper-iron sulfide deposition, given the lack of evidence of mixing of brines with low-salinity waters, the lack of correspondence of the ore zone with the initiation of phase separation, and no change in wallrock alteration style.

Abstract The Bingham Canyon porphyry copper deposit, prior to mining, is estimated to have contained 40.4 million ounces of gold and 289 million ounces of silver within 3,105 million tons of ore. The gold-mineralized zone mimics the shape of, and is coaxial with, the copper ore shell, but the zone of highest-grade gold mineralization lies at a slightly lower elevation than the zone of highest-grade copper mineralization. Geological observations suggest that high gold grades are associated with abundant bornite. The distribution of silver corresponds closely with that of copper. Gold and silver recoveries for Bingham porphyry ore have averaged 68 and 81 percent, respectively, since the introduction of froth flotation in 1920. Electron microprobe examinations of head and concentrate samples suggest that most gold occurs as particles less than 25 microns across and is alloyed with less than 15 wt percent silver. Most gold particles occur on the boundaries of chalcopyrite and bornite grains and as inclusions within those minerals. Gold, silver, and bismuth tellurides are present but rare. The mode of occurrence of silver is not well established, but based on the high silver recovery and the response of concentrator products to leach tests, most of the silver is inferred to be present in solid solution in copper sulfide minerals. Sequential leach tests suggest that approximately 10 percent of the gold in the ore is encapsulated in pyrite and approximately 5 percent is encapsulated in silicate minerals.