Search Documents

By N. Kanari

One of the criteria to define the market value of chromite concentrate is its chromium to iron ratio. Changing this ratio for a definite chromite mineral is impossible by physical processing. This study investigated the possibility of increasing this ratio through the carbochlorination and the oxychlorination of chromite concentrates. Experiments are carried out up to 1000 °C. The characteristics of samples and reaction products are determined by SEM, XRD and chemical analysis. The carbochlorination of a chromite concentrate at about 600 °C leads to the . selective partial elimination of iron allowing a higher Cr/Fe ratio of the treated concentrate. Selective extraction of iron could also be achieved at about 950 °C by oxychlorination. In this case, a part of chromium contained in the concentrate is recovered as chromium oxychloride. The obtained residue had high content of Cr, Mg and A1 oxides. Such material has probably better chemical and thermal properties that may. be useful for foundary and refractory applications. Two flow-sheets for the beneficiation of the chromite concentrates using carho- and oxychlorination are suggested.

Jan 1, 1997

By M. Suzuki, M. Dobashi, M. Kahata, T. Yoshida

Almost 30% of steel in Japan is produced by electric arc furnace (EAF) treatment of iron scrap. EAF dust includes approximately 20 wt % of Zn and 3- 5 wt % of CI and is treated by the pyrometallurgical processes to recover Zn as Zn oxide. Direct hydrometallurgical processing is one of the most effective methods to recover high purity Zn. In this case, CI in the EAF dust is dissolved in the liquid phase by leaching, and the CI anion in electrolyte attacks anodes which are commonly made of a lead base alloy. Several processes have been proposed to remove CI anions from acidic sulfate solution. In this study, an electrolytic process was examined to eliminate CI anions from Zn sulfate electrolyte. From our study it can be said that the elimination rate of CI anion depends on the anode material ( i.e., the elimination rate is Pb-Ag alloy == Pb > DSE== Pt). In industrial Zn electrowinning process, the electrolyte contains Mn, which means the influence of Mn should be considered in the elimination of Cl. Mn dioxide deposition on an anode plate reduces the efficiency of CI removal. A periodical reverse current electrolytic system was examined to prevent this efficiency decrease, and deposited Mn dioxide could be removed very rapidly when the current is reversed. More than 95% of CI anion could be removed by this method in a shorter period than direct current method.

Jan 1, 1997

Alluvial mining even of shallow deposits is often economically a marginal proposition and causes significant disruption of the land surface through the need for large scale excavation. In-situ leaching using chlorine-based solutions eliminates the need for excavation, the disruption of surface activities, and may greatly reduce processing costs and improve recovery especially of fine gold. A spreadsheet model has been developed to design and analyse the economics of in-situ leaching of alluvial deposits. In-situ leaching of shallow deposits may be achieved in a number of ways including solution infiltration via perimeter ditches or the use of injection and production wells. In most instances deeper alluvials may only be processed using well systems. Two deposits are analysed in this paper. The first consists of one metre of payable wash beneath one metre of overburden. Some thirty fields per year are treated processing 450 000 BCM per year at a cut-off grade of around $4/tonne ($8/rn3 or the gold value equivalent of 0.26 gh or 0.52 g/m3). The principal costs are well drilling and labour. Sensitivity analysis indicates that doubling the throughput halves the cost. The economics of the project are relatively insensitive to reagent costs and consumptions, and halving the recovery doubles the cut-off grade. Shallow deposits treated using the infiltration ditch system may be marginally cheaper and more conveniently managed although this depends on the relative cost of digging the perimeter ditches. In a second example, deep leads with one metre of wash beneath 30 metres of overburden necessitate significant drilling and feature reduced throughputs as a consequence. In the example chosen 30 fields a year are processed for an annual throughput of 65 000 tonnes costed at around $20/tonne (1.4 g/t Au equivalent, $40 /m3). Sensitivity analysis indicates that throughput, and drilling cost per metre are not important but there is a high sensitivity to recovery and to the depth to payable wash.

Jan 1, 1992

By Wendell E. Dunn

INTRODUCTION The early history of the chloride process has been recorded in a chapter of a Bureau of Mines bulletin (9 by one of the inventors of a chloride process, Stewart Croasdale, who is famous for the Pohle- Croasdale Process. The earliest use of chlorine in metallurgy was in 1557 by Bartholome Medina. But apparently even earlier there was knowledge that salt could be used in gold and silver extraction because a treatise, de la Pyrotechnica, published in 1540 in Venice, asserted that silver could be obtained from its ores by a wet salt process. In 1609 a priest, Alonzo Barba, invented a process using a copper vessel and boiling a solution of salt to extract silver chloride ores. The copper vessel was, of course, one of the reactants. This led to the Kronke process introduced in Chile in 1860 which substituted cuprous chloride for the kettle. A major step was taken in Europe in the late 1700's to chloridize roasted silver ores in combination with amalgamation using iron to reduce the silver chloride. By 1843 the Augustan process was introduced. Ores were roasted with salt and leached with a saturated salt solution. The silver chlorides passed into solution from which silver was precipitated by copper. In 1848 sodium or calcium thiosulfate solution of silver chloride was suggested by Dr. John Percy, and the idea was applied in 1856 by Von Patera in Bohemia.

Jan 1, 1983

By T. Inami

The chlorine leach of the anode slime was studied in order to improve the treatment process at the Niihama Nickel Refinery. The anode slime originates from the nickel matte electrorefining and, contains 3-5% of nickel as sulfides. A comparative study has been conducted on the filter cake resulting from the sulfur filtration of the molten anode slime. The kinetic factors of the chlorine leach such as temperature, grain size were defined. Under the optimized condition, 70-80% of the nickel is recovered from the slime or filter cake. On the basis of these results, the chlorine leach process for the treatment of anode slime has been established. The leaching plant has been installed and successfully operated since 1986.

Jan 1, 1988

By FRANK RIEBERS

IN DISCUSSING the selection of a geophysical method, much of what the writer will say is applicable to any of the various methods and to their use in prospecting, whether for oil or for other minerals. Specifically, the writer's subject is the problem, particularly pressing on the Pacific Coast, of checking the rising cost of the discovery of new fields by the proper employment of geophysical methods. Table I was prepared from statistics published by the California State Milling Bureau. The writer selected five of the largest a:ld most active companies operating in California, segregated the number of wild-

Jan 1, 1930

By Hans Lundberg, Basil T. Wilson, H. Steuart Scott

FOR the benefit of those readers who may not be in close touch with present practices in the geophysical prospecting for ore, brief reference will fiat be made to the advantages and shortcomings of the methods to be discussed. Magnetic and electric methods are generally accepted as the most useful for ore prospecting. By magnetic methods, magnetic intensities that are not normal may be recorded and outlined. From these can he located concentrations of such highly magnetic minerals as magnetite or pyrrhotite, which sometimes occur in such large masses that they are of economic value in themselves. More often. however, these magnetic min¬erals are associated with others, such as copper, zinc, lead, gold, and silver, which, if existing in sufficient concentration and quantity, may constitute valuable ore bodies. It is therefore only when pyrrhotite and magnetite are present in these bodies that the magnetic method can be used to indicate their presence.

Jan 1, 1945

By Håkan Stille, Jalaeddin Y. Rafi, Fredrik Johansson

"INTRODUCTIONIn tunneling projects, pre-grouting is performed with the purpose of establishing an impervious zone around the tunnel periphery. This is obtained by reducing the penetrability of the most conductive fractures in the rock mass. The main attention, besides economy of the project, is given to limiting the ingress of water into the tunnel to a certain amount during construction s well as operation period. Failure in pre-grouting process may, according to Bruce (2007), significantly affect the project in terms of safety, performance, cost and time. In this respect, determination of design parameters (pumping pressure, properties of the mix and stop criteria) affects these projects significantly. In current practices, depends on the geological conditions and requirements of the project these parameters differ widely. Weaver (1991) recommends selection of design parameters, specifically grout injection pressures, based on site specific factors and the conditions at each specific hole into which grout is to be injected (grout hole logging and water pressure test data). Houlsby (1990) correlated the allowable grouting pressure to the quality of the rock mass and the rock cover above the grouted fracture. In his methodology, grouting should be continued until the maximum pressure was attained. Later, Lombardi and Deere (1993) introduced the Grout Intensity Number (GIN), which limits the combination of injection pressure and injected grout volume in order to control the energy induced in the fracture i.e. avoid fracture jacking. Even though the GIN method was a step forward in understanding of the mechanism of the fracture deformation, there are ambiguities connected to this methodology, thus determination of the intensity number is challenging (see e.g., Rafi and Stille 2015)a.A main problem when no theoretical solution is practiced is that effects from the chosen injection pressure, such as possible increases of transmissivity and changes in total grouting time, remains hidden in the overall grouting process. The question is if a high or a low pressure should be used to fulfil the requirements of the projects at the lowest possible cost."

Jan 1, 2016

By S. Epstein

THE new low-alloy high-strength steels are obviously here to stay. With 75 per cent higher yield strength and 50 per cent higher tensile strength than plain carbon structural steel, they permit 20 to 40 per cent weight savings and 10 per cent or more increase in pay load in the con-struction of railroad cars, buses, trucks, and a great variety of material-handling equipment. Their cost is low enough so that the extra cost of the new lighter construction over that with carbon steel offers an attrac-tive self-liquidating investment; in some instances new construction with these low-alloy steels may even be as cheap as with plain carbon steel. A considerable and rapidly growing demand for the low-alloy steels has already sprung up. The many steel compositions that have appeared on the market lately 18,27,28,29,30 to meet this demand would seem to indicate that no single composition is uniquely fitted for the purpose. However, no doubt some compositions are more suitable than others. The purpose of this study was, therefore, to compare the effects of the various alloying elements that might be used in the low-alloy steels in order to choose the metallurgically most logical composition, paying due regard, of course, to the economic aspects involved.

Jan 1, 1936

"INTRODUCTION Foam, unless intentionally created, in any industrial process presents operational problems, or at a minimum, is a nuisance. Some foam problems are unique to a given industry and others are common across many industries. A few problems foam presents to any particular industry are: (a) Poor Housekeeping, (b) Environmental impact, (c) Safety Hazards, (d) Slower Production Rates and, (e) Reduced quality of the end product. Defoamers address these issues. Sadly, the assumption in most industries is all defoamers are alike. In reality, a lot of chemistry is involved in the manufacture of even the simplest defoamer sold today and rarely are any two defoamers “just alike”. Today’s defoamers can include polymer chemistry, fatty esters, alkoxylated alcohols, silicone chemistry, silicone surfactants, ethoxylated and propoxylated block polymers, and a tremendous amount of emulsion chemistry just to name a few. This paper will discuss the various types of defoamers, defoaming mechanisms, the advantages and disadvantages of defoamer selections, and how to choose the proper defoamer for your application. Before a discussion of defoamer can be brought about, foam generation and composition must be discussed. WHAT IS FOAM? Foam is a colloidal suspension of a gas dispersed in a liquid. Most often foam consists of air dispersed in water. If a stream of air is introduced into a liquid, the bubbles produced assume a spherical shape. As the density of the bubble is less than the liquid the bubble rises. When the individual bubbles reach and pass through a surfactant free liquid they collapse. Air from the bubble dissipates and the liquid previously surrounding the bubble flows back.It should be noted a pure liquid will not foam. In the case of air dispersed in water a surfactant is necessary to make the water support a stable foam. A surfactant is a term used to describe a surface active agent; a compound with a hydrophilic end and a hydrophobic end on the same molecule."

Jan 1, 2016

By Sami Hindstrom, Travis Orser, John Starkey

"A great deal of effort has been expended in the last 11 years by the authors and others to identify the correct power required to grind ore in a SAG mill, by developing ore hardness variability functions for the ore body to be mined. This paper describes the next step in the SAG design process, which is choosing a SAG mill to accomplish the required specified design performance.At the test work stage, each ore hardness data point is a unique and discreet bit of information that represents the energy required to grind the ore represented by that sample at optimum SAG conditions. When the design criteria are set, it is now considered necessary that the required power draw in the mill chosen be provided at optimum conditions as well.Based on actual 3-ft diameter pilot plant results, we can now show that the grinding efficiency and throughput drop when the optimum load limit is exceeded. Future work is expected to show a similar reduction in efficiency when exceeding optimum speed. Providing specified power by exceeding these optimum conditions is not adequate and leads to a lower cost but underperforming SAG mill.It is possible in some cases to modify a SAG circuit to force it to perform better, but this often takes time, much effort and costly modifications. In most cases the capital spent on a properly sized SAG mill may prevent production losses that would be many times greater over the extended start up period. This is the direct result of choosing the proper SAG mill at the start.INTRODUCTIONThe sequential steps required for the design of any grinding circuit, have changed dramatically in the last seven years. Previously, it was considered necessary to do six foot diameter SAG mill pilot plant tests on representative samples of minus six inch ore (F80), in order to understand design requirements. It can now be shown that this method is costly and not likely to produce the desired result because it is difficult to recover six-inch material from deep within a new mine. The representative nature of the sample is often compromised when the sample is selected."

Jan 1, 2003

By M. Saghaeian, R. Hejazi, H. Abedini, M. Zare

Water recovery in mineral processing plants is one of the most important subjects because water supply is a critical matter economically and environmentally, especially in desert areas. In this paper, the filtration behaviour of two iron ore tailing sample has been investigated using laboratory scale vacuum and pressure filtration units. These samples including tailing from Sirjan and Zarand concentrate production plants with the d80 of 94 and 41 micron, respectively. The results show that by using vacuum filtration the cake moisture content of Sirjan sample would be about 24%. But the filtration time is too long and vacuum belt filter cannot be used in industrial scale. Adding about 40 g/ton of flocculant would decrease the filtration time by about 30% and make the vacuum belt filter appropriate for dewatering of this sample. For Zarand tailing sample, the vacuum filtration would produce a wet cake by about 31% moisture content. Filtration time is too long and adding flocculant would not improve the results very much. So pressure filtration must be used for dewatering of this sample. The results of laboratory tests show that using pressure filter would reduce the cake moisture content to 21%. The filtration time is logical, so this process can be used for Zarand tailing dewatering.

Jan 1, 2014

By Hans Hamrin, Bruce Kennedy

Once an ore body has been probed and outlined, and sufficient information has been collected to warrant further analysis, the important process of selecting the most appropriate method or methods for mining can begin. At this stage, the selection is preliminary only, serving as the basis for a project layout and feasibility study. Later, it may be found necessary to revise the details, but the basic principles for the ore extraction should remain a part of the final layout. With respect to the basic principles employed, relatively few mining methods are used today. For the purposes of this presentation, the principles are classified as follows: 1) For naturally supported stopes, the available methods are room-and-pillar mining and sublevel stoping. 2) For artificially supported stopes, the available methods are shrinkage stoping, cut-and-fill mining, square-set mining, and longwall mining. 3) For caving methods, the available techniques are sublevel caving and block caving. Due to the uniqueness of each ore deposit, the variations on each of these methods are nearly limitless. It is impossible to include even the major variations in this chapter; the goal of this chapter is to present the principles as a guide to the mining engineer in adapting the general methods to specific needs. The selection process described herein is intended to supply the techniques by which the candidate methods available for a given ore body can be reduced to one or two feasible approaches. The feasible approaches then can be evaluated in detail, and the particular modifications can be investigated. In describing costs and economic factors, all values herein are expressed in terms of 1978 US dollars.

Jan 1, 1982

Provide guidance on the selection of millisecond initiator delays between blastholes in surface mine blasting to provide a desired degree of rock fragmentation consistent with safety and vibration considerations. The Problem Blasting remains the primary means of fragmenting, rock for all kinds of mining, quarrying, construction, and excavation activities, and it is the only practical and economic method of breaking up and moving large amounts of material such as coal overburden and stone aggregate. Because of the large amount of blasting done, typically using 4 billion pounds of explosive to break about 8 billion tons of rock annually in the United States, a small improvement in blasting performance will have a significant productivity impact. Standard blasting practices involve the selection of time delays in a blast for at [cast three purposes: (1) to control energy flow to minimize adverse vibrations, (2) to provide sufficient time relief for good rock displacement, appropriate muck pile shape for digging, and the prevention of collar violence, misfires, and flyrock, and (3) to provide an appropriate amount of interhole stress wave and gas pressure action for a desired fragmentation size distribution. Timing guidelines that exist are based on subjective observations rather than measurements, even for the relatively new casting methods. Until this Bureau study, no definitive analysis had been done to quantify the fragmentation and productivity of full-scale blast rounds as functions of precision delay timing.

Jan 1, 1989

By Lorne Roberts

"This paper describes: how Falconbridge's fire protection system meets the needs of the Lockerby Mine; why the system was chosen over other alternatives; how it is unique, but can be applied to any underground situation; details of the system; how it was installed; the role of a fire protection company; and general considerations when choosing afire-suppresant system.IntroductionIn May 1981, after about three years of searching for the best fire protection system for the re-opened Lockerby nickel mine at Whitefish, near Sudbury, Ontario, Falconbridge Nickel Mines Ltd. installed an AFFF type of fire suppression system. It was designed and supplied by the Fire Protection Systems Division of Levitt -Safety Ltd.The system protects against loss of life, equipment and/or production, and it complies with legislation should fire occur in a fuel storage area and/or scooptram garage and service bay at any or all of the three levels near Shaft No.2.About 18 months after Levitt-Safety began working with Falconbridge, the system was designed and installed at a cost considerably less than that which would be incurred if fire damage caused the loss of two days of production.The fire protection system, which overcomes a limited water supply, is a self-contained balanced pressure proportioning system. It senses the flow and automatically determines the correct concentration of foam to water. It is triggered by a release mechanism which operates a bank of nitrogen cylinders, which in turn pressurize a pressure vessel to expel the foam concentrate and water from the tanks. This solution is piped to sprinkler heads in the specific area."

Jan 1, 1982

By R Tom Watts

The blasting industry has changed more in the last five years than in any period to date. The equipment utilized to load boreholes has changed in response to more precise blasting products and programs, and the need to maintain tighter control over product formulations produced by bulk loading equipment. Tread Corporation has built over 1,300 heavy ANFO type bulk loading units currently operating in over 40 countries worldwide. These units have been designed to meet almost every possible loading scenario but there are always new situations that require special designs and configurations to meet the challenge. The focus of this presentation is to make you aware of the process that should be used to determine the equipment best suited for your application. We will discuss loading cycle times, delivery rates, multiple product mixing capability, capacities, manpower utilization, regulatory compliance, and where and when to use automation in the loading process. We will also discuss the suitability of chassis with regard to ground pressure, turning radius, terrain, weather conditions as well as highway suitability. The US Bridge Law as well as laws that cover the concept of axle loading and spacing will be covered. Through new computer aided design and modular design capabilities, you can now have almost any configuration required to meet your bulk loading objectives. We will also review the range of equipment currently available in the market place and discuss tradeoffs between price, capacity, and complexity.

Jan 1, 2000

Choosing the correct delay time for many blasting applications is an important and critical blast design parameter for controlling fragmentation, muckpile shape, swell, digability, throw, ground vibration and airblast. BAl and its affiliates have monitored thousands of full scale blasts in a variety of field conditions, spanning over 15 countries, with sophisticated blast monitoring instrumentation. In some blast environments, a small change in the choice of delay times used had a dramatic and pronounced effect on the overall blast results. In other blast environments, large changes in the choice of delays used had absolutely no effect on the final results in terms of specific outputs. In environments which were sensitive to the delay selection, the type of explosive, dynamic response time of the rock mass (TMIN), integrity of the material, burden and rock mass geometry, all played a very important ,role.

Jan 1, 1998

By S J. Henderson

Pumped co-disposal of coal processing waste was promoted in the 1990-2000s as a low-cost highperformance alternative to tailings dams. In particular it would avoid high up-front capital for rejects trucks and dam embankments, and would produce a combined waste deposit with better geotechnical properties than either coarse rejects or tailings. Overall, the promise was not delivered; in particular, upon discharge the waste segregated by size, and operators responded by moving the coarser waste to contain the finer waste. In consequence, not only did design analysis lag behind construction, but some of the initial expectations persisted with the result that analyses did not fully represent what was occurring on the ground. After more than twenty years inspecting, designing and tending Co-Disposal Areas (CDAs), it is apparent that they are essentially upstream constructed tailings dams with some more favourable aspects but also a few unique quirks. Although waste management technology has moved on somewhat, the high cost of changing CHPP waste circuits means that most mines with pumped codisposal will continue to discharge mixed waste slurry into CDAs. It is therefore worthwhile to share some lessons in the hope of promoting sounder design, operation and rehabilitation. These include: • Discharged waste does not form a homogeneous wholly competent deposit but instead comprises materials ranging from sandy gravel to silty clay with the distribution determined by movement of the discharge and decant structures; • CDAs circulate and contain a lot of water; • As a result of the first two points, some areas of the CDA comprise saturated fine waste that is no different from tailings and, like tailings, often behaves in an undrained manner; • Seepage is inevitable and desirable because strength improves as water is removed. However, stability is strongly impacted by pore pressures and in design these need to be rationally rather than optimistically considered; • As CDAs are built to about 40m or higher, strength-deformation characteristics of the foundation become more important; • Even if geomechanically stable, CDAs will need covers to prevent salts and acids from reaching the surface; and • Erosional stability of the cover material(s) will probably dictate maximum slopes for rehabilitation.

Jul 1, 2021

By William Gleason

"There are signs that the commodity downturn that has battered the mining industry for the past five years is beginning to ease up. As the dust begins to settle and mining companies begin to take stock of the battle, Newmont Mining Corp. will be one that is standing strong with just a few scrapes and bruises thanks in large part to the leadership of president and chief executive officer Gary Goldberg and his right hand man and chief operating officer, Chris Robison.As he closes in on retirement (for a second time) Robison, a third-generation miner from Nevada, took time to speak with Mining Engineering about a 33-year career in which, among other things, he is credited with not just helping Newmont survive the turbulent times but with steering the company to a safer, more productive and more profitable heading.“I think we did it better than anyone else,” Robison said when asked how the company fared during the past five years. “We didn’t talk about it a lot, we just put together a strategy and we delivered.”What Newmont, the world’s second-largest gold mining company by production, delivered since Robison took the position of chief operating officer in 2013 are improvements in costs, porduction, projects and safety.Operating under the mantra of “live within your means,” Robison was pulled out of retirement from Rio Tinto and into a challenging situation at Newmont. The price of gold was in a nose dive from a high of nearly $58/g ($1,800/oz) and heading to levels closer to $38.60/g ($1,200 oz).“Newmont is a big ship that can’t be turned, but has to be steered,” said Robison. “We recognized that we had to set a new course. The direction the ship was going was great for $1,600 to $1,800/oz gold but we were chasing ounces.”Like the rest of the gold mining sector before the falling gold prices, Newmont was focused on volume and was looking for gold wherever it could be found. The slogan at Newmont in 2011 was “7 million ounces a year by 2017.”When Robison came on board it was a different reality.“We had to begin focusing on value over volume as the cornerstone of Newmont going forward,” he said."

Aug 1, 2016

By J. Mikhael Erekson, Connie Campbell Brashear, Brent Meins

Christmas morning 2020, an IED in an RV was detonated along an evacuated section of downtown Nashville, Tennessee. The blast damaged over 40 buildings, including AT&T’s Main Central Office and caused internet and cell outages across 1,200 zip codes for three days including the airport and EMS services. Published investigations by the ATF and FBI were inconclusive in determining the explosive composition and size. Video captured a large fireball that may indicate a fuel-air-mixture explosion which would create lower peak pressures than high explosives, but longer pressure duration and significant impulsive loading. Blast pressures were amplified by reflections in the urban environment bordered by the 8-story AT&T building and a row of multi-story historic buildings. Some structures had little damage as they were shielded from the blast pressure by closer buildings, and seemingly far-field structures contained damage from the pressure wave after multiple reflections and propagation through porous parking garages. Damage to the reinforced concrete frame AT&T building included snapped masonry ties, cracking and spall to the closest column, and vertical displacement of the elevator, even with the brakes applied. The historic structures directly across the street from the blast partially collapsed. Initial damage included complete failures of unreinforced masonry façades, broken timber beams, and uplifted roofs. Secondary, progressive collapse took place over months as the brick walls and weakened historic mortar could not resist typical wind and environment loads. One of the close historic structures was renovated in the 1990’s and structural retrofits to comply with building codes were required. The addition of steel columns and façade tie-ins improved survivability and it remained standing with a high percentage of the front brick intact. Generally, the observed blast damage was related to a structural component’s mass and flexibility. Internal timber framing was unscathed, but many steel studs required replacement. Glazing damage was observed several blocks away and many roof membranes were punctured by falling debris. Secondary damage from broken sprinkler lines and loss of environmental control often led to more costly repairs than the initial blast pressure damage. The proliferation of bomb-making knowledge leads to hundreds of bombings each year in the US. Building risk considerations should include explosive threats along with other hazards. ASCE structural standards and design manuals have been published to address these risks and may be useful guides for building construction.

Feb 6, 2023