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By James J. Snodgrass

A new technique was used to obtain detailed sonic logging data in drill holes above the water table at a coal mine site in northeastern New Mexico. The equipment was developed under contract to the Bureau of Mines and the U.S. Department of Energy to indirectly evaluate the in situ structural properties of coal and overburden. The system comprises a hydraulically operated, wall-clamping downhole probe compatible with standard four-conductor logging cable, and a surface control module. Resolution of layering is 0.6 meter (2.0 ft), and a redundancy of data from separate receivers provides accurate timing measurements. Preliminary results in the settled overburden of an excavated long-wall panel indicated a low average velocity zone, extending approximately 18 meters (60 ft) into the immediate roof of the coal seam. Subsequent measurements improved the field and recording procedures to produce high quality waveforms from which both P and S arrivals may be visually interpreted. Over a representative section of interbedded sandstone, siltstone, shale, and coal, Vp and Vs varied considerably even within lithologic units. Compressional wave velocity in the coal seam, Vp = 1,740 m/sec (5,700 ft/sec), was in the range of variability of published data.

Jan 1, 1982

By J. Botula

In the region of the North-Bohemian Coal Basin and its environment, there, in a row of places, are found the accumulations of rocks of the sedimentary and pyro clastic origin, the preliminary composition of those shows the possibility of their being utilized for the production of ecologically sparing natural Fe- and Ti- pigments and filling substances. In many places of the regions of Chomutov and Podborany and near Bilina and also in other places, there are found raw stocks perspective for the preparation of yellow up to ochre-brown, red, brown-red and green dyes. The target of project is the verification of dispensable reserves, their mineralogical composition and chemical and physical attributes, verification of treatment ways of Fe-and Ti-pigments separation (hydrocyclones, magnetic and electrostatic separation) and their stabilization and technological painting attributes for applications in colors, coating and plastic masses, mortar mixtures etc.

Jan 1, 2014

Atlas Copco Construction and Mining Australia identified a number of issues in regard to the skill levels, labour turnover and productivity of our service technicians. In 1994 we were experiencing a labour turnover rate of 42 per cent per annum amongst our technicians. Exit interviews were held with each individual and one of the major areas of dissatisfaction was the degree of product training provided on our equipment, compared to what is required to be competent across the range of our products. These tradespersons were prepared to accept the reduced remuneration that an OEM offers, for the benefit of comprehensive, professional training that, in theory, could be provided. The truth is that we were achieving approximately 40 per cent of our target for training hours because of the demands of field service, pre-deliveries, etc. So, the summary was the same as the industry was experiencing at that time because of skilled labour shortages, production demands, etc people were employed and thrown in at the deep end. A recipe for failure that will be successful every time.

Jan 1, 1998

By L. P. Weber

During the years 1983-1987, a research programme, jointly performed by the steel producers ARBED, British Steel Corporation, Peine-Salzgitter, Unimetal, and co-sponsored by the European Community for Steel and Coal (ECSC), has been carried out on steel H-piles of different shapes. The initial aim of the testing programme has been the improvement of bearing capacity, both in sandy and clayey soils. At two test sites, standard H-beams are compared to H-piles with different types of laggings or to H-piles grouted both under low and high pressure. In this paper and in view of the open european market in 1992, the H-pile capacities and their corresponding allowable loads, determined from codes, recommendations and computation procedures in use in Belgium/Luxembourg (B/L), France (F), Federal Republic of Germany (G), and the United Kingdom (UK) as well as their evaluation from dynamic CAPWAP and Case methods are compared to the static capacities measured in-situ. In addition, procedures for estimating the load/movement behaviour of H-piles from CPT, pressuremeter, and CAPWAP are compared to the measured curves.

Jan 1, 1991

By Peter Radziszewski

"Typical mining operating costs can be divided between extraction (30 % to 70 %), comminution (30 % to 50 %) and separation (5% to 20% ). Cornminition process costs, representing an important contribution to mining operating costs, can themselves be divided roughly between energy (50 %) and linerkharge wear (50 %). Developing the ability of predicting mill wear will allow a more accurate estimation of wear costs. However, total media wear in a given ball mill grinding process is a product of three recognized wear mechanisms those being abrasion, corrosion and impact. Further, the contribution to total media wear of each of these wear mechanisms has not been well established. In this paper, a overview of abrasive, corrosive and impact wear mechanisms is made from which an empirical wear prediction procedure is proposed. Further, future directions in wear prediction research is outlined. INTRODUCTIONTypical mining operating costs can be divided between extraction (30 % to 70 %), comminution (30 % to 50 %) and separation (5 % to 20 %). Comminition process costs, representing an important contribution to mining operating costs, can themselves be divided roughly between energy (50 %) and lined-charge wear (50 %). With respect to wear, world wide steel consumption as grinding media is estimated at over 600 000 tomes per annum (Malghan, 1982). As such, developing the ability of predicting mill wear will allow a more accurate estimation of wear costs.Charge media wear prediction is actually estimated using the Bond abrasion test. From Bond abrasion index tests, it is possible to determine a wear rate using the following function:"

Jan 1, 2000

By D. L. H. Bulbring

The removal of a cylindrical core from thick-wall sections for creep analysis by the relatively new Weldcore® process represents a very exciting methodology for obtaining more representative creep damage data from large engineering structures. The cylindrical core that is removed, representing about 60% of the wall thickness, leaves a substantial removal site that needs to be repaired. This paper presents data pertaining to taper Friction Hydro Pillar Processing as an alternative repair technique for filling the core removal site. Process parameters were evaluated with special attention being paid to the effect of downward force on process response variables, weld defects, and mechanical properties of 10CrMo910 steel. Process temperature and torque response as well as total process energy input were also considered. This paper also assesses the static and dynamic performance of this repair technique. The influence of a varying downward force and the occurrence and position of discontinuities were quantified. Downward force was shown to have the most notable effect on weld joint dynamic performance and was found to be related to the process temperatures achieved in close proximity to the weld interface.

Jan 1, 2013

By S. Nikolic

"Calcium ferrite slags are currently used in a number of copper-converting processes. Despite the industrial importance of this system the phase equilibria have not been fully investigated. Characterization of this slag system is necessary to improve the control of process parameters, including fluxing and operating temperatures. Recently, a modified experimental method has been developed; this involves rapid quenching of slag samples equilibrated at high temperatures with the resulting phase assemblages analysed using electron probe microanalysis (EPMA). In the present study, experiments were completed under controlled temperatures and oxygen partial pressures using CO/C02 or H2/C02 gas mixtures. The investigated slags were supported during equilibration by a substrate of the primary phase. This technique removes the limitations arising from the use of crucibles and facilitates rapid quenching of the melt. Experiments were carried out at 1200°C and 1250°C (1473 Kand 1523 K) and in the composition range 0-40 wt.% Cu20, 0-25 wt. % CaO and 45-80 wt. % Fe203. Liquidus and solidus data are reported for the primary phase field of spinel between the oxygen partial pressures of 10-4.5 to 1 o- 6-5 atm. The analyzed compositions of liquids and solids are used to construct the phase diagram of ""Cu20"" -CaO-""F ez03"" system in equilibrium with metallic copper at fixed oxygen partial pressures."

Jan 1, 2007

By Edward C. Peterson

Recent studies indicate that the United States halt substantial reserves of ilmenite, one of the major titanium minerals. However, the studies showed that sources of rutile, another important source of titanium are limited. This paper summarizes and evaluates results and conclusions reached by the various investigations initiated by the Bureau of Mines and others pertaining to the titanium mineral resources of the Nation. Domestic occurrences of ilmenite that are economically exploitable by present-day beneficiation methods are found in Florida, New Jersey, New York, South Carolina, and Virginia. These deposits are estimated to contain 50.3 million tons of titanium dioxide (TiO2). Occurrences of ilmenite that cannot be processed economically under present technological conditions are found in California, Colorado, Minnesota, Montana, Oklahoma, Oregon, Rhode Island, and Wyoming. These reserves amount to 51.1 million tons of TiO2. Reserves of rutile found in the United States are estimated to be 1.8 to 2.1 million tons of TiO2. Other than occurrences in Florida and South Carolina, rutile is found either in small scattered bodies or in deposits where the mineral cannot be recovered economically by present beneficiation methods.

Jan 1, 1966

By William E. Souder

Behavioral accidents are a particular type of accident. They are caused by inappropriate individual behaviors and faulty reactions. Catastrophe theory is a means for mathematically modeling the dynamic processes that underlie behavioral accidents. Based on a comprehensive data base of mining accidents, a computerized catastrophe model has been developed by the Bureau of Mines. This model systematically links individual psychological, group behavioral, and mine environmental variables with other accident causing factors. It answers several longstanding questions about why some normally safe behaving persons may spontaneously engage in unsafe acts that have high risks of serious injury. Field tests with the model indicate that it has three important uses: It can be used as an effective training aid for increasing employee safety consciousness; it can be used as a management laboratory for testing decision alternatives and policies; and it can be used to help design the most effective work teams.

By D R. Seaman, B Adamson, F Burns, B A. Seaman, P Manton

The Telfer concentrator, located in the Great Sandy Desert of Western Australia, consists of a dual train gold/copper operation processing ore from one underground and, currently, two open pit mines with differing mineralogy. The flotation circuit of each train was designed to operate in several modes depending on the feed mineralogy. The majority of ore mined at Telfer is processed in a sequential mode where copper minerals are first floated into a saleable copper concentrate followed by the flotation of an auriferous pyrite concentrate which is treated in an on-site hydrometallurgical plant (carbon-in-leach (CIL)). Gold is recovered as a gravity product within the primary grinding circuit, to the copper concentrate, and to a lesser extent, the CIL circuit.Since Telfer was re-opened, with a new concentrator, in 2004, the processing plant has struggled with poor copper concentrate grades, partially due to the excessive entrainment of non-sulfide gangue minerals in the copper flotation circuit and, more recently, due to composite copper particles produced when processing ore from a supplementary satellite pit that has not previously been processed through the new Telfer concentrator. Gold recoveries in the CIL circuit have also been below industry standard. This paper presents the implementation of recent changes made to the circuit to address these performance issues. The reconfiguration of the circuit has involved the installation of the following major equipment items: two ISAMillsÖ in ultra-fine grinding applications (one in the copper circuit and one in the pyrite circuit), two Jameson Cells to improve fine gangue rejection and a bank of 5 + Outotec TC30s to recovery copper and gold from the reground pyrite stream. The equipment was purchased direct from vendors and an engineering firm contracted to design and install the multi-vendor reconfiguration upgrade.CITATION:Seaman, D R, Burns, F, Adamson, B, Seaman, B A and Manton, P, 2012. Telfer processing plant upgrade - The implementation of additional cleaning capacity and the regrinding of copper and pyrite concentrates, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 373-382 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Fuming Wang, Changrong Li, Dan Wu, Wei Shen, Yaxu Zheng

In order to improve the oxidation resistance of Cr–Mo–V steel for high-speed railway brake discs, a higher Cr was added to the steel. Effect of temperature on the oxidation behavior of brake disc steel with different Cr contents was studied by OM, SEM and XRD. The results show that the oxidation curves at 500 °C obey a linear oxidation law in 0–2 h and 2–20 h, respectively. The oxide layer is thin and the oxidation products are Fe2O3 and Fe3O4. The oxidation curve at 700 °C follows a linear law within 2 h. With the oxidation time extending, the oxidation curves follow a parabolic law and the oxide layer becomes thicker. Moreover, the oxide layer is divided into two layers. The outer oxide layer is loose and is mainly Fe2O3, while the inner layer is denser and consists of FeO and FeCr2O4. The oxide layer thickness reduces and the oxidation resistance of the steel is improved with Cr content is increased.

Mar 1, 2018

By R Redden

"The Didipio Gold-Copper project in the Philippines has been a well-defined reasonably high gold grade porphyry for almost two decades. OceanaGold are now bringing the project into production in late 2012 and have recently reoptimised the project with the goal of combining the inherent high grades with higher through-put than previously proposed that will see strong initial metal production. The project was discovered and well defined by 1995, but has seen some obstacles to development, namely sovereign risk, capital cost and project funding. The project strengths over this time that have kept the flames alive are: strong grades large orebody with low stripping ratios a simple beneficiation process and a clean high-grade concentrate strong support from the Philippines government.The initial study in 1998 used Gold and Copper price assumptions of $325/oz and $0.95 lb respectively. Today reserves are based on $950 and $2.85. So, being a porphyry with a large reducing grade halo, the deposit now lends itself to extraction on a much larger scale than before, without any significant capital expenditure as a larger open pit now dominates the project.Didipio is a game changer for OceanaGold, so it has been important to learn from history and to capitalise on a strong initial metal production profile. The project sits in a reasonably remote mountainous area of Luzon which sees annual typhoons and numerous short duration high intensity rainfall events and two rivers flowing through the project area, so it has not been without some innovative technical solutions.CITATION:Redden, R, 2012. Didipio - Learning the lessons, adapting and getting ready for production, in Proceedings Project Evaluation 2012, pp 67-76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 24, 2012

By Martin J. Gavin

"Before discussing oil shales it may be well to consider briefly the conditions surrounding the petroleum industry in the United States, because these largely explain why so much interest is being manifested in oil shales. The United States is not only the greatest producer of petroleum in the world, its output amounting to about 65 per cent of the world's total production; but is also the world's greatest consumer, using more petroleum than it produces within its own borders. For the past four or five years it has been necessary to import oil at a continually increasing rate to make up the deficit between domestic production and domestic consumption. Experts who have made a close study of the future supply and demand for, crude petroleum are satisfied that under present production practice and with the development of possible undeveloped productive areas, the gap between domestic consumption and production will steadily .increase.As possible solutions for the impending domestic shortage of oil, various expedients are receiving attention. These may be grouped under three heads, as follows:(1) Temporary measures, such as curtailment of consumption, development of more efficient methods of production, and more efficient utilization of supplies of petroleum still available. It is unlikely that there will be any great curtailment in consumption of petroleum in the United States; rather, consumption will continue to increase unless a real shortage of oil actually forces curtailment of consumption. The other two possibilities mentioned deserve, and are resolving, serious thought. Much experimental work along these lines, some of which has already yielded excellent results, is being done. Obviously, however, any of these remedies are temporary ones only, so far as regards domestic production of petroleum."

Oct 1, 1920

By R. V. Ramani

This volume, the first of a six volume final report, provides an executive summary of the research and results carried out under a grant from the U. S. Bureau of Mines on underground coal mine ventilation. Under the project, a mine ventilation simulator was developed. Sensitivity of leakage and friction factors on the total quantity and pressure requirements was studied. The simulator was applied to a new mine under development, and to an operating mine, to demonstrate the usefulness of the simulator in ventilation planning and in evaluating proposed changes to existing ventilation system. The titles of the other volumes are as follows: Volume II: Mine Ventilation Network Theory Volume III: User's Manual for PSU/MVS Volume IV: Sensitivity of Leakage and Friction Factors Volume V: Application of PSU/MVS to Ventilation Planning of a New Mine Volume VI: Application of PSU/MVS to the Analysis of Modifications to Existing Ventilation Systems

Jan 1, 1977

With increasing demand for real-time monitoring of mine parameters, the requirement for appropriate data management in many mining applications is also increasing. This includes atmospheric monitoring in underground coal and metal mines. Although a number of different (real-time) monitoring systems have been installed in underground mines, they all typically share the same systems or sub-systems, where each sub-system may include both custom hardware and / or software components. In addition, monitoring components installed in underground coal mines in the USA should also be intrinsically safe and approved by the US Mine Safety and Health Administration. Real-time analysis adds complexity to the system since data validation and storage should be completed independently of filtering, data reduction operations, or visualization. Real-time processing may include statistical evaluation, trending, cross-correlation, and real-time alarm or warning generation. This paper presents the concept and design of an integrated system under development for atmospheric monitoring in US coal mines.

Jan 1, 2014

By A. Takala, H. Cline, D. Girard

"This article describes the project development and successful implementation of a particle sorter at the Kensington mine. The Kensington underground gold mine and associated milling facilities are located within the Berners Bay Mining District on the east side of Lynn Canal about 45 miles north-northwest of Juneau, Alaska. The paper describes the project from concept, through the development phase, including test work confirming feasibility, to a discussion of operational data and includes shared experiences from operation and maintenance. The project has proven successful in recovering gold that was previously lost to the waste dump and has already resulted in a positive return on investment. The payback was achieved in less than one year.INTRODUCTION The first paragraphs of this paper describe Coeur Mining and the Kensington Mine, its history, geology, mining operation and mill. The second part of this paper gives a quick introduction to sensor-based sorting in general and X-ray transmission sorting (XRT) in particular. This article does not cover costs or economic impacts apart from the pay-back period for the investment at Kensington. Interested readers find more in information on this in the literature (Kleine & Wotruba, 2010; Robben, 2013). Since the publication about XRT sorting at TGME in Pilgrim’s Rest (Kleine, Riedel, Ketelhodt, & Murray, 2010), this is the first time that a comprehensive data set on gold ore sorting using XRT is published. Following chapters highlight the aim of the project for Coeur Kensington, project development through testing and operation before concluding. ABOUT COEUR MINING’S KENSINGTON OPERATION Coeur Mining is the largest U.S.-based silver producer and a significant gold producer with five precious metals mines in the Americas employing approximately 2,100 people. Coeur produces from its wholly owned operations: the Palmarejo silver-gold mine in Mexico, the San Bartolomé silver mine in Bolivia, the Rochester silver-gold mine in Nevada, the Kensington gold mine in Alaska, and the Wharf gold mine in South Dakota. The Company also has a non-operating interest in the Endeavor mine in Australia in addition to royalties on the Cerro Bayo mine in Chile, the El Gallo complex in Mexico, the Zaruma mine in Ecuador, and the Correnso mine in New Zealand. In addition, the Company has two silver-gold feasibility stage projects—the La Preciosa project in Mexico and the Joaquin project in Argentina. The Company also conducts ongoing exploration activities in Alaska, Argentina, Bolivia, Mexico, and Nevada. The Company owns strategic investment positions in several silver and gold development companies with projects in North and South America."

Jan 1, 2017

By A. J. Plumpton

Centrifugal air classification and li-quid-phase sedimentation are the principal methods of industrially sizing materials of dimensions smaller than those handled by screens. Increasing application of materials such as composites and high performance ceramics has furthered the need for closely-sized, fine, industrial mineral and synthetic products of controlled properties. Sedimentation can be used to separate very small sized particles but introduces problems of liquid-solid separation, de-agglomeration and drying. Some of the advantages and limitations of centrifugal air classification will be discussed and laboratory and plant measurements using centrifugal machines will be presented to support the discussion.

Jan 1, 1990

By A. W. Jolliffee

ANY attempt to forecast the mineral resources of a largely unknown region is hazardous and, in the case of the Northwest Territories, such a task is even more hazardous than usual. This is not merely because of the immense territory involved (over a million and a quarter square miles), only a small fraction of which has ever been explored or prospected, but also be-cause both the geology and mineral deposits thus far examined show many unique features, and, finally, because the region is being actively prospected at the present time. However, in view of the present widespread interest in Canada's mineral resources, a brief compilation of what is known regarding mineral occurrences and geology in the explored parts of the far north seems timely. From these assembled data, a few inferences are warranted as to future mineral production from this region. HISTORY The story of mineral discovery in the Canadian northwest is a fascinating one. As well, it abundantly illustrates the importance of mineral occurrences in indicating future mining possibilities. The same sequence of events has repeated itself too often to be merely fortuitous.? In most cases, the dis-covery of a mineral deposit of possible economic value has been foreshadowed by the finding of the valuable mineral or an associated mineral in the same district, generally in small quantity, by an early explorer or traveller. Thus, John Franklin reported oil seepages from the base of Bear Rock, near Nor-man, at almost the very spot where oil was struck nearly one hundred years later. Again, some would-be Klondikers, deterred by the hardships of the route, remained to prospect around Great Slave lake, and were the first to report the Pine Point lead-zinc occurrences there and the gold-bearing veins on Yellowknife bay. Sporadic prospecting followed at the latter locality for over thirty years before the recent rich strikes were made. Similarly, in 1847, Dr. John Rae picked up a boulder of copper ore south of Rankin inlet, on Hudson bay. More than eighty years later, a body of copper-nickel sulphides carrying values in platinum metals was found at this locality. Also, the report of cobalt bloom on the east coast of Great Bear lake brought back by a Geological Survey of Canada party in 1900 was a factor in the events leading to the discovery of silver and radium there in 1930.

Jan 1, 1937

By D J. Corp

The Halmahera Contract of Work is a sixth generation contract held 82.5 per cent by Newcrest Mining Limited and 17.5 per cent by PT Aneka Tambang and takes in the Gosowong Project area. In 1991 Newcrest Mining Limited established a small exploration office in Jakarta and proceeded to seek exploration opportunities. The Halmahera area was identified as a substantial prospective ground position in a relatively unexplored area. In late-1991 Newcrest Mining Limited and PT Aneka Tambang agreed to explore in Halmahera. Initial field work commenced in July 1992. A vigorous ground reconnaissance programme led to the discovery of the Gosowong deposit a little over 12 months later in September 1993. In April 1997 the Contract of Work was approved covering much of the island of Halmahera. Between September 1997 and November 1998 activities were directed principally towards obtaining the necessary permits required to commence construction activities. Some particularly ambitious targets were set for achieving this outcome. An aggressive construction programme commenced in late-1998. Construction took place during a period of unseasonally high rainfall, which in itself presented additional challenges to the construction team. A key milestone for the project was achieved on 1 July 1999 when wet commissioning of the process plant commenced. Construction of the Gosowong Mine was achieved on time and within budget. A period of some six years elapsed from the initial discovery of the Gosowong deposit to the time of the first gold pour. Much of the permitting, construction and commissioning activity took place between September 1997 and July 1999. This coincided with a period of significant social, economic and political upheaval in Indonesia. During the construction period a high level of importance was placed on the structured recruitment and training of local people, as well as fostering appropriate community and local business development programmes in the communities nearby the project. Emphasis was also placed on environmental management with detailed long-term planning and progressive rehabilitation commencing during the construction phase. The permitting and subsequent development of the Gosowong Project has demonstrated that even during the difficult times, with commitment, it is possible for mining and exploration companies to conduct business in Indonesia.

Jan 1, 1999

By A Singh, C Da Corte

Banded Iron Formations or more commonly known as BIF are sedimentary rock formations with alternating silica-rich layers and iron-rich layers that are typically composed of iron oxides (hematite and magnetite), iron-rich carbonates, and/or iron-rich silicates. Considering the depletion of highgrade iron ore reserves in South Africa, there is a need to maximise resource utilisation through the exploitation of sterile resources in particular BIF material which makes up greater than 65 per cent of current reserves. BIF, like most resources, is non-renewable and the deposition of BIF is thought to have come about by the reaction of Fe2+ ions in the ocean water with dissolved oxygen billions of years ago. BIF ore derived from the Limpopo region in South Africa (SA) located in the Penge Iron Formation is according to Cairncross, Kramers and Villa (2018) equivalent to that contained within the Asbestos Hills Iron Formation of the Transvaal Supergroup in the Northern Cape, SA. Considering that these are one of the largest iron ore deposits in SA, the case study involved mineralogical characterisation followed by beneficiation of BIF from these two regions to ascertain the comparability. Coarse and fines gravity separation comprising of Heavy Liquid Separation/Dense Media Separation on the +1.18 mm size fraction and shaking table on the -1.18 mm size fraction was conducted to ascertain whether an on-grade product or blended feedstock could be produced. The Limpopo mixed and Northern Cape conglomerate BIF samples achieved similar overall responses due to the conglomerate sample containing 15.3 per cent additional -1.18 mm fines. A combined coarse and fines product grading at 60 per cent Fe could be achieved at a yield and recovery of 43.9– 53.0 per cent and 62.2–63.8 per cent respectively. Increasing the grade to 63 per cent Fe reduces the overall recovery by 13.3 per cent. At the higher target grade, the contaminant specifications could be achieved for both samples. The Northern Cape laminated BIF sample is the most promising of the three samples studied. At the two iron target grades overall yields and iron recoveries of 72.9–65.4 per cent and 85.2– 80.2 per cent was achieved. In both instances the silica grade exceeded the product specification, however if the silica content is the driver the target iron grade should increase to 63.32 per cent. This will result in a minimal decrease in recovery of 0.4 per cent. The promising results of this study indicate that coarse beneficiation of BIF material is possible. These ore types could be blended with superior grade products to improve overall yields and recoveries or sold directly at a 63 per cent Fe product grade whilst sacrificing 0.4–13.3 per cent recovery.

Nov 8, 2021