Recoverable Gold Research Articles

Technological studies of gold ore using centrifugal concentration methods

Relevance. Te use of gravitational enrichment methods, in particular centrifugal concentration, is based upon the presence in gold-bearing ore, along with fnely disseminated free coarse gold, which is not fully recovered in the process of cyanidation and fotation. Te purpose of the work is to conduct technological research on the centrifugal concentration of gold-bearing raw materials in order to assess its applicability in the production process. Te main objectives of the study were: studying the material composition of the sample, conducting tests to determine the gravity recoverable gold (GRG test), as well as tests using a centrifugal concentrator with continuous concentrate discharge (CVD test). Object of study. Te paper presents the results of studies of the enrichability of gold-bearing ore using centrifugal concentration methods. For research, a sample weighing 160 kg, with a size of –100 mm was taken. According to the phase analysis data, when the ore was ground to a fneness of 94,8% of the –0,071 mm class, the amount of free gold was 66%. Te rest of the gold in the amount of 33.9% is found in intergrowths and flms, including closed intergrowths with sulfdes (4,06%) and quartz (3,7%). Based on the results of the research, conclusions were made about the properties of the ore of the deposit and the optimal conditions for its processing (grinding size, concentrate yield) were determined by gravity methods. It has been established that the studied ore is efectively enriched by gravity methods. Centrifugal separation at an intermediate size of 64,6% class –0,071 mm with a low concentrate yield works efciently. A concentrate with a gold content of 432,0 ppm was obtained with a yield of 0,07% and a recovery of 32,04%. Te level of gold recovery by gravity with staged ore grinding (GRG test) is quite high – 53,97%. Te optimal yield of gravity concentrate during enrichment at the KC-CVD concentrator was 10,55%. With this yield, gold recovery was 82,28% at a grade of 7,77 ppm.

Evaluating the effectiveness of fine gold extraction technologies on the example of titanomagnetite beach placers of the western coast of Kamchatka

The material on the gold content of coastal-marine deposits of the western coast of Kamchatka is analyzed and the resource potential is briefly characterized. A review of gold technological estimates obtained from the study of gold-bearing samples taken in promising areas of the coastal-marine strip, from the Bolshaya Vorovskaya River in the north to Cape Levashova in the south, is presented. Stock materials supplemented by our studies were used. Gold-bearing deposits with very fine (0.05-0.1 mm) and fine (0.1-1.0 mm) gold amounting to 94.6 % were tested, as well as samples with gold up to 2 mm and more in addition to fine gold The content of freely recoverable gold reached 91.9 %. In the case of significant gold reserves in placers, prospects for their commercial development open up. experiments on the enrichment of gold-bearing coastal-marine deposits of Western Kamchatka indicate the possibility of extraction of free gold and other valuable components from them. Gravity technologies and modern equipment developed by ОАО Irgiredmet and JSC ITOMAK are the most effective for their extraction. enrichment of gold-bearing formations with simultaneous extraction of several useful components from them, which is possible with the use of fluoride technology, can also become economically advantageous.

Characterization of amalgamation tailings from ASGM in Sekotong area, West Nusa Tenggara, Indonesia, and its potential added value

Artisanal and small-scale gold mining (ASGM) in Indonesia still uses mercury in amalgamation process to extract gold form the ores. The process easily produces gold but at the same time produces very dangerous mercury waste. In this study, a comprehensive series of tests were carried out on amalgamation tailings from the ASGM in Sekotong area, West Nusa Tenggara. The tailings contain mercury up to 150 ppm, above the safe threshold, and gold up to 20 ppm which is intended to be recovered. Furthermore, mineral liberation analysis (MLA) and gravity recoverable gold (GRG) test were performed to determine the feasibility of recovering gold from the tailings. The liberation degree of the gold started from particle size of 37 \\xm causes challenging to recover it. However, the GRG test confirmed that the gold was still feasible to be recovered by gravity concentration.

Hydration of alkynes to ketones using cobalt ferrite magnetic nanocatalyst encrusted with gold nanoparticles

A magnetically recoverable gold nanocatalyst supported on the surface of cobalt ferrite nanoparticle has been synthesized. Initially, CoFe2O4 magnetic core was prepared by ultrasound assisted co-precipitation method which was further surface functionalized using 3-mercaptopropyltriethoxysilane. By a precipitation process, highly dispersed Au nanoparticles were loaded on the surface of the thiol-functionalized magnetic core. Au (0) magnetic nanocomposite thus synthesized was used as catalyst for hydration of alkynes. The nanocomposite showed excellent catalytic activity for hydration both the alkyl and aryl alkynes in presence of 2 wt% of the material to generate corresponding ketones under microwave irradiation. The new catalyst could be easily recovered using an external magnet and could be reused without significant change in its activity.

Mineralization and hydrothermal alteration in the Mamão orogenic gold deposit, Andorinhas greenstone belt, Carajás Province, Brazil

The Mamão gold deposit, located in the eastern portion of the Amazonian Craton, northern Brazil, is hosted by mafic rocks of the Mesoarchean Andorinhas greenstone belt. An underground mine was operated in this area by Troy Resources Ltd., which produced approximately 350 koz of gold between 2008 and 2015. The hydrothermal alteration halos are characterized by a distal zone (10- to 80 m wide) with a chlorite-albite-epidote-actinolite assemblage, an intermediate zone (5- to 20 m wide) marked by calcite-albite-chlorite-actinolite-quartz, a proximal zone (0.5–5 m wide) composed of biotite-quartz-calcite-pyrite-(gold) and a quartz vein-hosted orebody zone (0.5- to 6 m wide) composed by quartz-calcite-pyrite-(gold). Geochemical data indicate that the metabasalt, metandesite and metadacite host rocks display a tholeiitic N-MORB signature, suggesting that they were formed in ancient oceanic spreading centers. Hydrothermal chlorite of the Mamão deposit is classified as ripidolite and brunsvigite. Biotite is the main mica and increases in modal content from the distal alteration to the vein zone, displaying compositions within the annite domain. Muscovite occurs as very fine lamellae and is generally located in the intermediate zone of the altered region. Amphiboles are calcium-rich and display compositions mostly varying from hornblende (Mg-hornblende to Fe-hornblende) in the distal zone, to actinolite in the intermediate zone. Sulfidation occurs in all hydrothermal alteration zones, with both fine- and coarse-grained pyrite as the main sulfide phase, and lesser amounts of chalcopyrite, pyrrhotite, cobaltite and sphalerite. Fine-grained pyrite contains many gold inclusions and is typical of the orebody zone preferentially in close contact with the proximal hydrothermal zone, whereas coarse-grained pyrite (without recoverable gold) occurs in the veins. From the edges to the core of the hydrothermal alteration halos, the As, Sb, Ag and Au contents in the pyrite increase, whereas Pb, Co and Mo decrease. Gold occurs as free crystals (2- to 0.1 mm) disseminated within the gangue or as inclusions in the fine-grained pyrite. Temperature estimated via chlorite geothermometer ranges from 284- to 320 °C, with pressure between 1.12 and 1.34 kbar according to biotite geobarometer calculations for the hydrothermal zones. The C–O–S isotope analyses of the calcite and pyrite from the orebody zone yielded δ13C, δ18O and δ34S values ranging from −4.23 to −3.54‰, 8.60–9.77‰ and 3.37–3.52‰ respectively, which suggests that the hydrothermal fluid is predominantly of metamorphic origin. The εNd (3.0) calculated using isotopic analyses of the metavolcanic host rocks varies between +0.11 and + 4.25. A whole-rock Sm–Nd isochron age of 2952 ± 14 Ma was obtained from the host rocks, while a post-mineralized pyrite yielded a Sm–Nd isochron age of 2446 ± 35 Ma. The deposit exhibits mineralogical and isotopic characteristics consistent with those of orogenic type containing gold-bearing, sulfide-rich quartz veins. The Mamão deposit's host rocks are among the oldest rocks described so far in the Carajás Province. The age of the mineralizing event is limited between 2.95 and 2.45 Ga (probably ca. 2.7 Ga), which is the major metallogenic event of gold-deposit formation in several granite-greenstone terrains worldwide.

Increasing gold recovery from poor ore using gravity

The article discusses the issues of increasing the efficiency of extraction of gold-bearing ores from poor ores using gravity using combined geotechnologies at the Sigiri mine (Republic of Guinea). Gravity Recoverable Gold (GRG) is defined as gold present in a particle in sufficient quantities to be selectively recovered from waste rock by gravity methods. Since Guinea is one of the ten leaders among the countries of the African continent in terms of gold reserves (2019 — 700,000 tons), it should be taken into account that the complex of measures for ore processing includes crushing modules interconnected during the technological process, grinding-gravity module, flotation module and metallurgical a module that affects the solution of the problem of integrated development of subsoil in the generally accepted understanding and this is the maximum extraction of recorded reserves from the subsoil and useful components from mined ore. The author presents the influence of the centrifugal concentrator Nelson (Knelson) on increasing the degree of gold recovery from gold-bearing poor ores under high climatic conditions. Increase in gold production by the GRG test method due to the destruction of the ore structure and a significant decrease in density, as well as an increase in the opening of minerals using gravity up to 63 %. Thus, the optimization is classified as medium-coarse gold.

Prerequisites for Processing a Foam Product in the Process of Bacterial Oxidation of Gold-Bearing Concentrates in a Separate Cycle

The recovery of gold from refractory ores and concentrates is a significant problem in the modern gold processing industry. The use of bacterial oxidation technology at the Navoi Mining and Metallurgical Combine (Uzbekistan) made it possible to increase the share of recoverable gold during the processing of refractory ores from the Kokpatas and Daugyztau deposits. However, during the operation of the biological installation, a problem arose of abundant foaming in bacterial oxidation reactors. This article is devoted to the issue of foaming during biooxidation and its negative impact on the oxidation process. Methods of combating foaming and the choice of the optimal solution, providing for the processing of bio-oxidation foam in a separate cycle, have been analyzed.

The Effects of Pulp Rheology on Gravity Gold Recovery in Free Milling Gold Ore of the Tarkwaian Systems of Ghana

ABSTRACT Gravity gold characterization provides a comprehensive understanding on the effect of mineralogy, particle size, and liberation on gravity concentrator performance. This is of significant economic importance for gold ores with a high amount of coarse gold particles. In this study, the effect of pulp rheology on gravity recoverable gold (GRG) was investigated using a single-stage GRG test on paleoplacer gold deposits of the Tarkwaian system of Ghana. The elemental and mineralogical composition of the gold ore was characterized using ICP-MS, XRD, and QEMSCAN analyses. Bench-scale gravity concentration was performed on the gold ore at varying clay contents (in the range of 5–30 wt.%) using Lab Knelson concentrator in the absence and presence of NaOH (2.5 kg/t) and CaO (2.5 kg/t). The mineralogical analysis showed the ore is oxidized and comprised 88% Quartz, 8% muscovite mica, 2% hematite, and 2% kaolinite. Liberation and association analyses showed 58% of the gold particles were liberated, 1% formed binary with quartz, and 41% formed complex aggregates with other mineral phases. The gravity concentration of the ore without clay material yielded 51% Au recovery (11.2 g/t) at the grind size of 80% passing 106 µm. Partial replacement of the ore with clay material at 5%, 10%, 15%, 20%, and 30% decreased gold recovery from 51% to 25.7%, 12.7%, 8.8%, 5.1%, and 1.5%, respectively. Subsequent conditioning of the slurry with NaOH improved gold recovery due to possible improvement in slurry rheology. However, the addition of CaO decreased gold recovery due to an increase in slurry viscosity.

Photocatalytic Oxidation of Alcohols Over Magnetically Recoverable Gold Supported Iron Oxide Nanoparticles

A one-pot simple and efficient synthetic route for the synthesis of Au-loaded Fe2O3 nanoparticles was developed, and this material's photocatalytic activity for visible light assisted oxidation of alcohols and degradation of organic dye were studied. As-synthesized nanostructured catalyst was characterised by powder X-ray diffraction (XRD), transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), SEM-mapping, X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherm (BET), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). It was observed that 5–10 nm Au-nanoparticles supported on 10–80 nm Fe2O3 shows boomerang-shaped nanoparticle. Gold loading of 1 wt% shows high conversion and selectivity towards the target product aldehyde. The synthesized nanomaterial also proved to be an excellent photocatalyst for degradation of organic dyes such as methylene blue (MB) and rhodamine B (RhB). The catalyst proved to be noteworthy as it does not loss in its catalytic activity even after five cycles of reuse.

Geometallurgical Studies on Gold Ore for Enhanced Comminution and Leaching

Many gold processing plants are experiencing challenges as mining pits are becoming deeper, rocks are getting harder and more complex polymetallic and refractory ores are being encountered. The variations in the characteristics of ores lead to deviations from the established parameters, and these affect gold extraction efficiency. This paper presents a study where geological characteristics of the ore types from some mining pits were used to ascertain the influence of ore blends on improving the performances of comminution and leaching circuits. To achieve this, mineralogical, comminution, gravity recoverable gold and leaching investigations were conducted on fresh and weathered ore samples and their blends. Mineralogical study showed that the main rock types associated with the mine pits were dolerite, phyllites, conglomerates and sandstone. The dominant minerals were quartz, plagioclase, with traces of pyrites. The Crushability Work Indices of the rocks were between 30 and 37 KWh/t, which are generally higher than the maximum design value of 31.9 kWh/t, and this situation will pose throughput challenges in that section. The Bond Ball Mill Work Indices of the blends tested were between 16.4 kWh/t and 9.6 kWh/t and a blend ratio of 85% fresh and 15% weathered was found to have a Bond Ball Work Index almost equal to the design value of 14 kWh/t. With gold assays of 2.5 g/t for dolerite, 2.1 g/t for phyllite, 3.7 g/t for sandstone and 3.4 g/t for conglomerate, the gravity recoverable gold was in the order of sandstone 36% > phyllite (31.5%) > dolerite (29.5%) > conglomerate (18%). The overall gold recoveries were in the sequence of conglomerate (95%), sandstone (94%), phyllite (92%) and dolerite (87%). This information could be utilised in developing a proactive plant operations strategies for an operating plant in order to ultimately manage the plant and enhance achievement of set targets. Keywords: Geometallurgy; Ore Blends; Characterisation; Communition Circuit Performance; Gold Recovery

МОРФОЛОГИЯ И СОСТАВ ЗОЛОТА КОР ВЫВЕТРИВАНИЯ ТОМЬ-ЯЙСКОГО МЕЖДУРЕЧЬЯ

Актуальность. Коры выветривания пород палеозойского фундамента Томь-Яйского междуречья являются потенциальными объектами промышленной добычи легко извлекаемого золота. Но морфология и состав этого золота изучены очень слабо, что затрудняет оценку уже выявленных рудопроявлений и определяет актуальность выполненной работы. Цель: исследовать химический состав и морфологические особенности самородного золота в профиле кор выветривания Томь-Яйского междуречья. Объект: самородное золото в корах выветривания по породам палеозойского фундамента Томь-Яйского междуречья. Методы. Морфологические особенности золота, парагенетические ассоциации с рудными и жильными минералами изучались микроскопически под бинокуляром, в отраженном свете. Химический состав золотин определялся методом ИСП-масс-спектрометрии и на сканирующем электронном микроскопе TESCAN VEGA 3 SBU с ЭДС OXFORD X-Max 50, на рентгено-флюоресцентном микроскопе HORIBA Scientific XGT-7200. Результаты. Выявлены две формы нахождения золота в корах выветривания и первичных рудах – свободное и связанное (невидимое) золото. Определен химический состав и проба первичного и гипергенного золота. Установлено уменьшение содержания примесных элементов и увеличение пробы в гипергенном золоте по сравнению с золотом первичной минерализации. Описаны основные морфологические типы золотин разных частей разреза коры выветривания. Предполагается присутствие гипергенного золота «бактериоморфного» происхождения. Все разновидности гипергенного золота ассоциируют с гипергенными минералами (карбонатами, глинистыми минералами, гидроокислами железа). Наибольшие содержания золота характерны для верхней части разреза коры выветривания – зоны гидролиза остаточной коры выветривания и переотложенной коры выветривания.

Geometallurgical Study of a Gravity Recoverable Gold Orebody

Sheeted vein gold deposits are often characterised by multiple sub-parallel veins and free-milling coarse gold. Inherent mineralisation heterogeneity results in grade and process parameter variability, which increases project risk if not quantified. Measured grade variability is often exacerbated by poorly designed sampling and testwork protocols. Protocols that are optimised within the framework of the Theory of Sampling (TOS) to suit the ore type, together with quality assurance/quality control systems, will reduce variability and provide fit-for-purpose results. Geometallurgy can be broadly split into two key approaches: strategic and tactical (or operational). The strategic approach focuses on the whole orebody and long-term life-of-mine view, whereas tactical geometallurgy relates to a more short- to medium-term view during mining. The geometallurgical approach requires spatially distributed samples within a deposit to support variability modelling. Diverse attributes from core logging, mineralogical/textural determination and small-scale tests are used to measure variability. This contribution presents a case study that emphasises an early-stage strategic geometallurgical programme applied to a gravity recoverable gold (GRG) dominated deposit. It exemplifies how data can be acquired from a well-designed and planned programme to support resource estimation, a pre-feasibility study, trial mining and fast-track to production. A tactical geometallurgical programme is embedded into the mine operation.

ChemInform Abstract: Magnetically Recoverable N‐Heterocyclic Carbene—Gold(I) Catalyst for Hydroamination of Terminal Alkynes.

We prepared a magnetically recoverable gold(I) catalyst by immobilizing an N-heterocyclic carbene–gold(I) complex on magnetite and applied it to the hydroamination of alkynes. By employing 2 mol% of the magnetite-supported gold(I) catalyst, the hydroamination of terminal alkynes proceeded smoothly to provide the corresponding imine in a fair chemical yield. Moreover, after the reaction, the magnetic gold(I) catalyst was readily recovered by use of an external magnet and could be reused up to five times.

Magnetically Recoverable Gold Nanorods as a Novel Catalyst for the Facile Reduction of Nitroarenes Under Aqueous Conditions

In this work, cysteine-functionalized Fe3O4@Carbon magnetic nanoparticles were used for the synthesis of gold nanorods. Fe3O4@C nanoparticles were first prepared by synthesis of Fe3O4 magnetic nanoparticles (MNPs), and then carbon-coated MNPs (Fe3O4@C) were synthesized by glucose carbonization using a hydrothermal method. Finally, the gold NRs were loaded on the modified surface of Fe3O4@C MNPs. The designed magnetically recoverable gold nanorods, after full characterization by FTIR, SEM, TEM, TGA, VSM, XRD, and ICP-OES, were applied to the reduction of nitroarenes. The Fe3O4@C@Cys–Au nanorods showed higher performance than Fe3O4@C@Cys–Au nanospheres in a selective facile reduction of nitroarenes to the corresponding aminoarenes in aqueous medium at room temperature using NaBH4.

Preparation of magnetically recoverable gold nanocatalysts with a highly reactive and enhanced thermal stability

A novel method has been developed for the preparation of highly active and thermally stable Au nanocatalysts, including a ZrO2-TiO2 (hereafter referred to as ZT) mixed oxide layer, a moveable Hollow Fe3O4 (hereafter referred to as HwFe3O4) magnetic core and some Au NPs of 5–8 nm. This method involves the in situ reduction of Au NPs on the C/HwFe3O4 nanospheres by using the C layer as the reducing agents. SEM, TEM, EDX, and XRD were employed to characterize the prepared samples. The results showed the ZT layer could increase the thermal stability and reactivity. The reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) was employed as a model reaction to test catalytic performance in this work. The results showed the ZT/Au/C/HwFe3O4 nanospheres calcined at 750 °C showed the highest catalytic activity, compared to the samples calcined at 550 °C and RT, respectively. Meanwhile, the sample (750 °C) still has certain of magnetism, suggesting the desired samples could be separated by magnet. Finally, the catalyst was reused for several cycles to reduce the nitrophenol.

Magnetically Recoverable N-Heterocyclic Carbene–Gold(I) Catalyst for Hydroamination of Terminal Alkynes

We prepared a magnetically recoverable gold(I) catalyst by immobilizing an N-heterocyclic carbene–gold(I) complex on magnetite and applied it to the hydroamination of alkynes. By employing 2 mol% of the magnetite-supported gold(I) catalyst, the hydroamination of terminal alkynes proceeded smoothly to provide the corresponding imine in a fair chemical yield. Moreover, after the reaction, the magnetic gold(I) catalyst was readily recovered by use of an external magnet and could be reused up to five times.

Placer gold sampling—The overall measurement error using gravity concentration on particle size ranges during sample treatment

Author Summary: Placer deposits are generally characterized by low grade of free gold. This is the case in French Guiana where the main placer deposits are in the river bed. Most have already been exploited by very small mining companies using sluices. If this technology is efficient for coarse gold, it releases fine gold in the tailings. During the last years, studies have been performed on various sites and recoveries have been estimated between 40 and 60% depending on the size distribution of gold particles and of the quality of the sluice configuration. Many recent or ancient tailings are available with a non-negligible quantity of remaining gold, offering retreatment opportunities. They are generally found in the form of sand heaps with the shape of an alluvial fan originating at the sluice discharge. Due to the resulting large distribution heterogeneity it is necessary to take many samples at many strategically deployed locations. These samples have to be large enough to be representative of the local material. As gold is mainly liberated in this type of lot, traditional sample treatment with successive size reductions and sub-samplings is not efficient and can be very expensive. Another approach using sieving and gravity concentration per particle range is preferred and presented here. After presentation of the sampling and measurement protocol used, this paper focuses on estimation of the overall sampling error. Various tailing cases are presented for which retreatment decision depends on the level of confidence obtained for the estimate of the quantity of recoverable gold.

Effects of sample mass on gravity recoverable gold test results in low-grade ores

Gravity recoverable gold characterisation methodologies are the single- or three-stage tests, which generally use a standard feed sample mass. A case study of low-grade coarse gold-dominated mineralisation is presented that demonstrates the high variability of test results using different sample masses. Samples were processed using the single-stage test and subsequently entire development rounds were batched through a plant for comparison. Unsurprisingly the results indicate that the small (≤50 kg) test samples grossly understate plant gravity recoverable gold and display poor precision. Larger samples display improved precision, but still understate plant gravity recoverable gold. The small mass samples are unrepresentative as they do not contain the full gold particle size distribution. Poor representivity is enhanced by gold particle clustering. Small samples generally capture finer more abundant and disseminated gold particles, but rarely contain clustered gold. The use of standard GRG test sample masses is challenged. Test work should be based on spatially distributed representative field samples, that if required are split to representative sub-samples for testing. An early stage gold particle size characterisation programme is required to optimise sample mass and improve representivity.

Development of a laboratory test to characterise the behaviour of free gold for use in a combined flash flotation and gravity concentrator model

Currently there is no process model which simulates the behaviour of gravity recoverable gold (GRG) in flash flotation unit operation. Once developed, such a flash float model could be incorporated into an existing model for gravity concentration. Together, the integrated gravity recovery-flash float model will provide a tool for predicting the recovery of GRG in a closed milling circuit using both batch centrifugal concentration and flash flotation. In order to design a flash flotation model, a reliable laboratory method to characterise the response of GRG when subjected to flash flotation conditions has been developed. This paper details the evaluation of the effects of various chemical (reagent concentrations, sulfide presence, etc.) and operational (airflow, agitation, etc.) parameters on the overall GRG recovery by lab scale flash flotation. Of the factors evaluated, free gold flotation was found to be most impacted by potassium amyl xanthate (PAX) and copper sulfate reagent levels, as well as agitation speed and sulfide mineral additions.

Performance curve approach to optimising fluidising water for Knelson concentrators

Centrifugal concentrators such as Knelson concentrators (KCs) are commonly used in most gold processing plants to recover fine liberated gold particles. The decision to employ a gravity recovery circuit is primarily based on the amount of gravity recoverable gold (GRG) in the ore among other considerations. However, the conditions required to optimise the gold recovery in such devices used in plants cannot be determined by GRG test results as the separation of particles is based on the particle bed dynamics within the given unit which are different to those encountered in a three inch KC used for the GRG test. The significant operating variables that affect the performance of a KC are the size distributions of the gold and gangue, rotational speed of the bowl, fluidising water flowrate and the cycle time. Of these variables, the rotational speed is generally fixed, and the size distributions of the gold and gangue are determined by the comminution circuit employed. Thus, the fluidising water is the key variable that can be used to control the dilation of the particle bed to maximise the recovery of gold. This paper examines the validity of the GRG test for performance evaluation and discusses an alternative method based on performance curve of the device that can be used to evaluate the optimum fluidising water flowrate of an operating machine. The principles of determining the performance curve of the machine and its use are also discussed and illustrated with laboratory and plant data.