After more than a century applying flotation to the mining industry, two completely different strategies have been introduced for processing purposes. One is the classical approach viz. grinding the ores to a certain extent and floating them via conventional mechanical and recently pneumatic cells e.g. Jameson and Imhoflot^TM cells. This strategy continuous because mines face up to declining cut-off grades, complex and poly-mineralized ores, and they require to achieve an acceptable degree of mineral liberation. The other school of mind deals with the coarse particle processes mainly owing to the low energy needs, that includes flash, fluidized bed and HydroFloat^TM cells. The third and newest system proposes processing both fine and coarse sizes by flotation machines like oscillating grid flotation (OGC) and Reflux flotation cells. The present paper endeavours to critically evaluate these concepts from several points of view including existing technological elaborations, water and energy usages, kinetics and circuit design. Brief introduction of advanced technologies, along with their applications, were presented. It was revealed that the incorporation of coarse grinding apparatuses, mineralogical techniques together with the technologically applicable classification systems and adapted simulator tools are urgent needs for coarse flotation as the future requirements for mining industries. However, fine particle flotation may remain as the main focus of re-processing tailings dams.

In lines 5 and 6 iron ore concentrate production plants of Gol-e-Gohar Complex (Sirjan, Iran) the special surface of concentrate (Blain) is increased by the high pressure grinding rolls (HPGR).At present, due to changes in the input feed of the plant, the magnetite concentrate moisture has increased. Increasing the moisture content of the material will reduce the HPGR operational gap, thereby reducing the feed rate and the effective pressure on the particles. As a result, Blain of Concentrate was reduced. In the present study, the effect of several surfactants on the filtration rate and cake moisture content of Gol-e-Gohar iron ore concentrate was investigated using a laboratory scale vacuum filter. Four surfactants were used to study their effect on moisture, cake formation time and throughput. Chemicals was Sodium dodecyl sulfate and sodium lauryl ether sulfate (SDS and SLES, anionic surfactant), Polyethylene glycol (PEG, nonionic surfactant) and Cetyl trimethylammonium bromide (CTAB, cationic surfactant). filtration tests was carried out at optimal conditions of operating pressure, dewatering time, particle size, and solids content of pulp respectively 60 Kp, 120 second, 105 micron and 60% w/w. results indicated that by adding 100 g/t SDS and SLES, the filter cake moisture content reduced from 9.2 to 7% (wet weight base). So they was effectiveness more than other surfactants. The SDS increased filtration efficiency by decreasing cake formation time, increasing the filtrate volume and throughput. The use of SDS and SLES improves filtration performance by increasing the ratio of throughput to moisture (Φ= throughput/moisture). At a dose of 100 g/ton SDS and 75 g/ton SLES, the lowest moisture of filter cake and the highest throughput was achieved. The ratio (Φ) for those was highest compared to other surfactants. The results showed that SLES had the same SDS results as 75 g /ton. SLES was chosen as the final filter aid because of it has better performance on reducing the moisture content of the cake, reducing the cake formation time, higher throughput, cost-effectiveness and availability.

Wetlands and aquatic ecosystems, which are an important part of the ecological system and national resources that need to be well managed, are becoming polluted by toxic heavy metals (HMs) from industrial, mining and smelting of metalliferous ores, and agricultural activities. The loss of wetlands may cause loss of flora and fauna, and decrease biodiversity.

Water logging resistant plants and their root associated microbes (Arbuscular Mycorrhizal Fungi (AMF) and plant growth promoting rhizobia (PGPR) can provide potential tools in Constructed Wetlands (CWs) in order to Nano-Mycorrhizo-Phytoremediation (NMPR) of HM-polluted natural wetlands and aquatic ecosystems. AMF-CW systems should be considered ideal inhabitants of technical installations for Phytoremediation and need to be optimized in efficient functioning of Phytoremediation in field trials.

This presentation will address one of the major hurdles in the production of large quantities of indigenous and stress-adapted AMF inoculum for the purposes of constructing artificial AM-CW systems. Significance and potential role of floating islands of aquatic macrophytes like Vetiver grass and their root associated microbes (AMF and PGPR) in environmental cleanup of HMs contaminated industrial, municipal, and mining effluents, will be highlighted in the presentation. During the Environmental and pollutants stresses, the aquatic macrophytes and their root associated microbes produce nano- molecules of HM-binding cysteine-rich peptides, phytochelators (Nano-molecules) forming HM-complexes which sequester HM- ions, protecting the host from contaminants. HM-adapted AMF not only enhance Vetiver grass growth producing greater biomass for bio energy production but also uptake/stabilize HMs , e.g. Nano-Mycorrhizo-Phytoremediation (NMPR).

The rapid growth of population and fast urbanization has resulted in the reduction of the good quality of available land. Black cotton (BC) soil is one of such problematic soils, though they are very fertile soils, they are not suitable for the foundation of roads and buildings. They are expansive clays with a high potential for shrinking or swelling as a result of changing moisture content. Due to the intensive shrink-swell process, surface cracks appear during dry seasons. A small amount of rainfall, such as 6mm can make these soils impassable for all traffic. About 23% of the area in India is covered by BC soil. To utilize expansive soils effectively, proper ground improvement techniques are to be adopted. One of the most widely used technique is to stabilize the expansive soil with conventional admixtures like lime, Ground granulated blast-furnace slag (GGBS), cement, and fly ash. Lime is an inorganic mineral that primarily contains calcium oxide and calcium hydroxide. GGBS is a by-product produced in blast furnaces used to make iron (mineral). In the present study, an attempt is made to modify the engineering properties of black cotton soil. This research work presents the improvement of engineering characteristics of expansive soils using lime and GGBS as an additive. For experimental work, lime of 2%, 4%, and 6% is used, and corresponding 5%, and 10% of GGBS is used. Tests like the California bearing ratio test, unconfined compression test, proctor test, Atterberg’s limits were performed. After stabilization, it was found that the unconfined compression strength and California bearing ratio of soil increased significantly.

The southeast region of the Amazonian Craton has been the target of several metallogenetic surveys, which recently led to the identification of the world-class Volta Grande gold deposit with gold reserves of ~ 3.8 Moz at 1.02 g/t. This deposit is located ~60 km southeast of Altamira city, Pará state, and is hosted in the Três Palmeiras intrusive-greenstone belt, itself located in the northern Bacajá Tectonic Domain (2.24 – 2.0 Ga). A mylonitized, high-level intrusive suite hosts the mineralization. Local kinematic indicators point to dip-slip movement with the greenstone moving up relative to the intrusive rocks. Native gold mostly occurs as isolated grains in centimetric quartz veins and veinlets associated with pervasive carbonatic alteration that was synchronous to dynamic metamorphism. Part of gold is also associated to sulfide disseminations in this generally low-sulfide mineralization. These relationships are compatible with orogenic lode-type gold systems elsewhere. New petrographic studies from core samples along the stratigraphic profile reveal the presence of lava flows and dykes of rhyodacite, rhyolite, and subordinated microgranite crosscutting earlier style of mineralization. These rocks are characterized by potassic, propylitic, sericitic, and/or carbonatic hydrothermal alteration in selective, pervasive, or fracture-controlled styles. Within the hydrothermally altered rocks, gold occurs as disseminated isolated grains or replacing sulfides. Both native gold and sulfides are also hosted in centimetric quartz veinlets. Such features of the deposit are similar to those of the porphyry-type and low- to intermediate-sulfidation epithermal systems already identified in the Amazonian Craton. These data indicate a second mineralizing event, a common fact in large-tonnage gold deposits, and is now proposed for the Volta Grande deposit that can represent a new exploration guide.

Inorganic electrolytes present in the process water used during froth flotation may have both beneficial and detrimental effects. These effects are said to be ion specific as some ions may result in enhanced froth stability, increased mineral recoveries and decreased concentrate grades while others may bring the opposite effects. Onsite process water quality variations have intensified the need to understand the relationship between inorganic electrolytes and flotation reagents on flotation performance. The use of mixtures of thiol collectors in sulfide flotation is a common practice across the globe, however very little investigations have considered these in process waters of varying compositions. This study considers the effect of common cations, Na⁺ and Ca²⁺ in process water on the behaviour of mixtures of thiol collectors. Single salt solutions of NaCl and CaCl₂ at an ionic strength of 0.0213 mol.dm^-3 were used to investigate the behaviour of mixtures of two thiol collectors. These were carefully selected so as to understand how mixtures of thiol collectors behave in the presence of a monovalent cation versus a polyvalent cation. Bench-scale froth flotation tests were conducted using a Cu-Ni-PGM ore from the Merensky reef. The results have shown that the divalent cation, Ca²⁺, resulted in higher %Cu and Ni recoveries at all collector mixtures compared to the monovalent cation, Na⁺. The concentrate grades were however slightly compromised as slightly more gangue reported to the concentrate in the presence of Ca²⁺. This behaviour is attributed to the effect of polyvalent cations on bubble coalescence and froth stability.

It was experimentally shown that the chemical composition of biofilms on the surface of carbonate and other Ca-bearing rocks significantly affect the ratio between crystallizing calcium oxalates (whewellite Ca(C₂O₄)·H₂O and weddellite Ca(C₂O₄)·(2.5-x)H₂O) and their morphology.

It was established that metastable weddellite crystallize in the range of stable whewellite, provided that calcium concentration in the initial solution is higher than the concentration of oxalate ions, or with the addition of small amounts of organic acids (citric malic, succinic, and fumaric). Without whewellite, weddellite formed in more alkaline conditions (at pH>5.7). In the presence of citric acid, weddellite formed almost solely (as small dipyramidal crystals). With the addition of malic, succinic, or fumaric acids to the medium (separately or together), the amount of weddellite crystalls decreased, but the size of its crystals increased. The simultaneous presence of a number of chemical impurities typical of biofilms (K⁺, Mg²⁺, Sr²⁺, Cl^-, SO₄^2-, CO₃^2-, PO₄^3-) in the crystallization medium in addition to citrate ions, also lead to the formation of practically monophasic weddellite, represented by very small, poorly faceted, isometric crystals. The addition of these components individually or in pairs lead to a decrease in the amount of crystallizing weddellite relative to whewellite (especially in the presence of phosphate, carbonate, or strontium ions) with a simultaneous increase in the size of weddellite crystals.

The added micro components actively interact with crystallizing oxalates, either replacing Ca²⁺ ions or adsorbing on the faces of growing crystals. The presence of two series of solid solutions, isomorphous (Ca,Sr)[C₂O₄]·(2.5–x)H₂O) (sp.gr. I4/m) and isodimorphous Ca[C₂O₄]·H₂O(sp.gr. P₂₁/c)−Sr[C₂O₄]·H₂O(sp.gr. P ̅1) was experimentally proven for the first time. Additionally the presence in the medium of strontium (together with phosphate), potassium (only in significant amounts), as well as carbonate, magnesium and sulfate ions add tetragonal prism facets to the morphology of dipyramidal weddellite crystals, which can be explained by their selective adsorption on the edges of the latter.