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By Jamal Rostami, Asok Ray, Samer S. Saab Jr., Wenpeng Liu

Ground instability, such as roof or rib failures, is one of the most serious and frequent safety hazards that occur in underground mining, tunneling, and underground construction. The ground-related parameters and features of interest, in assessing roof or rib failures, are location, frequency, and orientation of the joints, voids, as well as rock-strength. These parameters are the main components of rock mass characterization that offers effective strategies for ground support, which, in turn, allow one to mitigate the risks related to ground instability. The main objective of this study is to determine the location of joints and classify rock-strengths by analyzing the drilling data recorded from an instrumented roof bolter while drilling for rock bolt installation during the operational cycle. For this purpose, computer programs based on updated pattern recognition algorithms were developed for joint-detection and classification of rock types to offer an estimated strength. This paper briefly introduces ongoing research on joint detection, especially for joints with an aperture less than 0.125in (3.175mm), by employing an instrumented roof bolter in controlled environments. To improve the capability and precision of joint detection programs in detecting the joints from the drilling data and reducing the number of false alarms, many laboratory tests with various simulated joints and rock-strengths were carried out at a J.H. Fletcher & Co. facility. This paper reviews testing procedures, data analysis, updated algorithms used for joint detection, and discusses the latest round of testing in samples with simulated joints at various angles along the borehole.

Jan 1, 2017

By M. D. Scott

"Highland Valley Copper recently installed a semi-mobile in-pit crushing and conveyor system designed to feed both the Bethlehem and Lornex concentrators with a feed averaging 120000 tonnes per day. The system installed with a rated capacity of 12000 tonnes per hour is the highest capacity hard rock semi-mobile crushing and conveying system currently in existence.The system is designed in a manner that the crushers can be moved easily as the pit is developed in depth with conveyors extending deeper into the pit, and conveyors being moved radially from a surge pile located at the rim of the ultimate pit as the pit increases in size laterally.The system consists of two 6000 tph, 60 by 89 Krupp semimobile crushers feeding two moveable 4500 hp, 60 in. conveyors, 1.25 km long feeding a 7500 tonne live storage surge pile. Two 96 in. belt feeders installed in reclaim tunnels under the pile feed two parallel 4500 hp, 60 in. conveyors, 1.25 km long on a 12 per cent uphill grade to the two existing Lornex plant feed conveyors. A third 96 in. belt feeder, under the pile, feeds a 60 in. conveyor, loading trucks hauling crushed ore to the Bethlehem mill.A description will be given: (1) of the system's design features in which climatic extremes, operating, and maintenance characteristics were of primary importance; (2) of the way the system was constructed from components purchased internationally on an extremely tight construction schedule; and (3) of the way the system has operated during the first few months in operation during which time it demonstrated that it has met various design criteria."

Jan 1, 1988

By M. T. Long

The Crestmore Limestone Mine of Riverside Cement Company in Riverside, California is situated within 1.6 km of the Santa Ana River. It is an alluvium covered deposit with a massive quartz manzonite intrustion separating the upper and lower limestone beds which dip from 30° to 50°. The highly fractured upper bed contacting the Santa Ana alluvium contains many unique water inflow problems which vary, from multiple high pressure 19 liters per minute inflows up to 3,000 liters per minute to 11,000 liters per minute inflows-contacted by development mining in April 1983. A case history of the successful grouting of these inflows and the continual grouting procedures in advance of present mining with empirical' results are discussed.

Jan 1, 1984

By Marvin P. Barnes, John G. Simos

The Park City District, Utah, is situated in the Wasatch Range at the intersection of the westward extension of the axis of the Uinta Range. Ore has been mined almost continuously from the first discovery in 1869 to the present day, with a total production of over 14 million tons. Sediments of Carboniferous to Triassic age have been folded into the northerly plunging Park City anticline and subsequently modified by thrust faulting, diorite and diorite porphyry intrusions, and strong east-west normal faulting during the Laramide orogeny. Younger andesitic volcanics partially cover the eastern edge of the district. The ore bodies occur as both lode and bedded replacement deposits over widely scattered localities. Near surface, high-grade silver "bonanza" ores were mined in early days from the Ontario and Daly Lodes, which occur along the east-west zone of faulting near the center of the district. Other lode or fissure deposits were found along the Mayflower and Hawkeye faults to the east and southeast. Large bedded replacement silver-lead-zinc ore bodies associated with east-west zones of fissuring, have been mined from favorable horizons in the Park City Formation in the Daly West and Judge mines. A series of long, narrow, high-grade, replacement ore bodies occur in the Silver King mine at a single horizon in the Park City Formation. Ore is currently being mined from strong bedded replacements in the Humbug Formation near the apex of the Park City anticline. Factors controlling ore deposition are: magmatic source, structural feeder systems, and favorable host rocks. Ore deposition along favorable beds is primarily a function of physical conditioning and secondarily of chemical composition.

Jan 1, 1968

By Nick Barton

The ability to estimate that support is unnecessary for various dimensions of opening in certain rock mass environments is of particular relevance in the mining industry, where most excavations are not expected to remain open indefinitely. As Hoek1 observes: "the basic aim of any underground excavation design should be to utilize the rock itself as the principal structural material, creating as little disturbance as possible during the excavation process and adding as little as possible in the way of concrete or steel support". Approximately two hundred case records have been analysed for the purpose of determining the amount of permanent support normally used when a given span is excavated in known rock mass conditions Some thirty cases concerned unsupported openings. Excavations that can stand unsupported appear to have certain common characteristics as regards rock mass quality. However, the mechanical properties of the rock mass are not the only factors controlling the choice of design. The dimension of the opening (span or height) and the type of excavation are two important variables.

Jan 1, 1975

This publication summarizes, for potential contractors and all other interested parties, the research and development of in-house and contract projects programmed by the Bureau of Mines for fiscal year 1983 (October 1, 1982-September 30, 1983) under its Health and Safety Technology program. The objective of these projects is to provide an ordered and sequenced series of advance toward the Bureau's overall goal of providing the systems technology required to create a more healthful and safer working environment for the Nation's mining and minerals processing workers.

Jan 1, 1982

By Angela Binder, Mareike Schubert, Yichen Jiang, Sandra Nowosad, Oliver Langefeld

GermanyINTRODUCTIONThe mining industry is currently characterized by various factors such as environmental impact, resource scarcity, social responsibility and geopolitical uncertainty. The production of minerals required to meet the demand for renewable energy is expected to increase by 500 % by 2050, particularly for critical minerals such as graphite, lithium and cobalt 1. Easily accessible deposits are often depleted, meaning that deeper and more complex deposits need to be developed. Furthermore, investors’ value systems have shifted towards more sustainable practices. Alternative approaches to solving this problem are therefore currently being developed, such as the Modular Mining Systems concept for scalable and adaptable mining projects 2. Many mining companies have also taken important steps to become more sustainable, implementing measures such as proactive closure strategies, restoration programs and the development of renewable energy projects. In the European Union, laws such as the Critical Raw Materials Act and the Net Zero Industry Act support the mining industry 3,4. They see it as important for the energy transition and promote more sustainable ways of working in the industry Particularly negative environmental impacts such as land degradation, scarcity of local water resources, water pollution and greenhouse gas emissions are ingrained in society’s memory. Despite these efforts, the public image has not yet changed. To change this perception, the industry must strive to better communicate its sustainable practices and the steps it is taking towards a more responsible and sustainable future, promote transparency and build trust.Digitalization, automation and electrification are driving the digital transformation in mining. However, their implementation can lead to higher capital expenditure, limiting their adoption across the industry. Furthermore, implementing new technologies can be a daunting task for any organization. Change management comes into play when introducing such disruptive technologies. It involves preparing an organization for change, potential resistance and establishing effective communication. This helps to ensure that the implementation is successful and the benefits of the new technology are maximized. Digital transformation requires well-trained, young mining, electrical, mechatronic and software engineers with a deep understanding of information systems. Unfortunately, the industry faces the enormous challenge of attracting this younger generation, who have little interest in the extraction of raw materials. The need for action is compounded by an aging active workforce heading into retirement and the forecast of increasing demand for critical minerals.In this challenging environment, the concept of Blue Mining with its constant further developments represents a promising approach. This implies a shift from a linear to a sustainably oriented circular economy. For the mining industry, this specifically means the introduction of innovative technologies, the increased recovery of materials from waste and the consistent questioning and application of circular principles along the entire life cycle of a mine. Such a change can not only reduce the environmental impact, but also contribute to economic resilience and increased social acceptance of mining.

Feb 1, 2025

By Tim O’Neil

More than 5,300 mining professionals from around the world attended the SME Annual Meeting and Exhibit, March 1-3 in Denver, CO. Seventy three technical sessions highlighted innovative technologies and applications for the development of mineral resources. And the exhibit featured 421 companies worldwide and 632 exhibit booths. The 1999 SME Annual Meeting had 10% international attendance. Professionals from outside the United States were guests at the first SME International Reception.

Jan 1, 1999

By J Nixon

I have to say that my story is not too much different to many others who grew up and worked in the great mining fields like Broken Hill, Mt Isa, Rosebery, Kalgoorlie or Kambalda and any one of them could have stood up here and spun you a good yarn.What does my paper offer you in this volume? By sharing my experiences I want to encourage you to consider your own experience with leadership, taking on change, learning from and contributing to the development of others.I have been very fortunate to be part of many new innovations into underground mining over the past 40 or so years; most of it with Conzinc Rio Tinto Australia (CRA)/Rio Tinto operations.•From hand-held drills and a homemade single boom Jumbo mounted on an old Airtrak, to the sophisticated twin boom jumbos with high speed drifters all controlled by an on-board computer;•from a Scraper winch and a Wagner 2D loader to fully automated electric LHDs that navigate to the tipple, empty the bucket and return to where they come from;•from hand-held cut-and-fill and timber stoping in Broken Hill to the bulk mining methods of a block cave where at Northparkes we mined more ore in a month than we mined in the total five years of operations at Currawang;•from hand-held scaling and bolting with no skin protection to installing ground support with Jumbos and sophisticated Cable Bolters and the introduction of in cycle shotcrete;•from hand-held ladder rising and shaft sinking to Box Hole rigs, Raise Bore Machines and Blind Hole shaft sinking; and•from Gelignite based AN60 stick explosives, ANFO, fuse firing and half second detonators to Powergel, Emulsions and electronic computer programmed detonators that can somehow be initiated by ‘Blast Ped’ travelling through the rock.

Mar 21, 2011

By J. Hadjigeorgiou, T. R. Stacey

This paper introduces the Quantified Value-created Process (QVP), a decision-making process for use in mine design and operation. The implementation of the QVP is founded on a ten-step rock engineering design process and a ten-step strategic planning process. The potential of this approach is demonstrated by examples of value created as a result of good research, design, and planning. The QVP is divided into two parts, namely, a ‘planning the process’ section and an ‘implementing the process’ section, and can be considered to be an extension of the risk approach. All costs, direct and indirect, associated with a significant mining decision (design, operational, investment) must be quantified in advance of committing to that decision, to determine the value that will be created in the short, medium, and long terms. Ethical values, associated with health, safety, the environment, public perception, and social aspects, may be difficult to quantify in economic terms, but must nevertheless also be considered. In contrast with a traditional risk approach, the QVP will identify the upside, and allow executives to make more informed strategic decisions. In this context it is essential to actively engage upper management in the decision process.

Feb 2, 2022

By W. Roggenthen, Z. J. Hladysz, G. D. Callahan, W. G. Pariseau, W. Weinig, C. Randolph-Loar, R. Popielak

A Deep Underground Science and Engineering Laboratory (DUSEL) is being planned at the site of the former Homestake Gold Mine in Lead, SD, under the sponsorship of the U.S. National Science Foundation (NSF) in cooperation with the Department of Energy (DOE). This national facility will host a variety of multidisciplinary science and engineering experiments, including physics experiments that require shielding from cosmogenic radiation. Current plans include construction of large rooms (up to 55 m in width) at depths of 1.48 km (4,850 ft) and 2.25 km (7,400 ft) below the surface. Preparation of the preliminary design required the development of a geotechnical characterization program, including preliminary drilling and coring, core logging, drill hole mapping with a televiewer, drift mapping of the geology and rock structure, in situ stress measurements, and laboratory testing of the mechanical properties of the rocks and discontinuities. Overall rock quality is very good to excellent. Site investigations included geotechnical assessments for the construction of caverns and laboratory modules. The results are favorable and reaffirm selection of the Homestake site for establishment of a Deep Underground Engineering and Science Laboratory.

Jan 1, 2011

"No true conception of the Park City mining district can be obtained without first giving consideration to the part it has played as a consistent producer of mineral wealth. Its position in this regard is almost unique in the annals of a lead silver camp. For over fifty years it has been a continuous producer of lead and silver and for twenty years it has added to the world's supply of zinc. Few camps with its productive history are so little known to the mining fraternity for the reason that its life has never been punctuated by periods of ""boom"" which serve to attract general attention, neither has it been the field of operation for promoters who temporarily focus attention upon their scene of action. Its history is one of legitimate mining operations. These were at first carried on by a number of smaller companies. A period of consolidation followed and at the present time the entire production of the camp is in the hands of two major companies and one smaller company. These are flanked by a number of prospecting properties, which are at this time actively engaged in the search for ores and later events will doubtless put some of them in the producing class.A technical discussion of the ore occurrence and mining operations in the camp will be the subject of a paper to be read before this meeting of the Institute. The mission of this article is to supply a ""Baedeker"" where Baedeker is lacking.The town of Park City is a typical, up-to-date, western mining camp which owes its existence as a town of 4,500 inhabitants solely to the mining industry. The camp is located 7,000 feet above sea level, thirty-two miles east of Salt Lake City. It is situated on the Victory Highway seven miles from its junction with the Lincoln Highway and has the benefit of excellent automobile communication with the metropolis of the state. Both the Denver and Rio Grande and the Union Pacific Railroads give daily train service to the camp and effectively solve the transportation problems of the mining companies."

Jan 1, 1925

By James T. Curry

The steady growth of the Northwest portion of the United States over the past two decades, and the very rapid development of Northern California, Western Nevada, and Oregon in particular, led the Calaveras Cement Company people to Shasta County, California in 1957. The presence of a large deposit of high calcium carbonate limestone had been recognized for many years, but it required the momentum of an expanding economy to make these long known reserves valuable. This, plus the availability of a reliable supply of fuel in the form of natural gas, and the ready means of shipping the product to the consumer both by highway and railroad, seemed to offer the proper combination to launch a successful venture. The Calaveras Cement Company had been manufacturing cement by the wet process since 1925 at their plant at San Andreas, California. Starting with two small kilns, the plant in Calaveras County started an expansion program in 1945 that ultimately resulted in the plant as it exists today, consisting of five kilns with a combined production of 4.5 million barrels annually.

Jan 1, 1967

By John V. Beall

Cutting costs and increasing safety with new ideas is the byword with The Cleveland-Cliffs Iron Co. on the Marquette Range in Michigan. Among the new ideas being tried out are mechanical shaft mucking, prefabricated lagging to replace timber poles, Carset bits in shaft sinking, and rubber tired guide wheels on the ore skips. Plans are being made to stockpile ore with conveyor belts during the winter. In sinking the Mather "B" Shaft a 3/8-yd clamshell-type bucket is used for mucking. The clamshell is opened and closed by means of a verticallymounted hydraulic ram actuated by 5000 psi oil pressure. An Ingersoll Rand-type hoist is used to raise and lower the clamshell. The hoist is controlled by one member of the crew on the floor of the shaft. When the bucket is raised, the men swing it over the muck pile to the desired position and then it is lowered on to the broken rock. The 1400-lb weight of the bucket causes it to sink into the broken rock and it digs as the ram closes the bucket. The hydraulic ram is operated by a man on the lowest shaft steel set who controls a specially designed oil pump which supplies oil pressure. The clamshell is emptied.

Jan 1, 1949

By Thomas R. Kuesel

In simpler times, construction was a cooperative undertaking. The frontier tradition of barn-raising is the construction equivalent of the academic ideal of a single student seated on a log with Horace Greeley. In a more complex world, ideals become more elusive. Still, it was only a generation ago that toll revenue bond financed projects generally involved a team composed of investment bankers, engineers, and construction contractors, who all shared a common objective -- to create something useful, at minimum cost and in minimum time, with fair compensation to all involved. In an increasingly contentious public climate, the team has too frequently been splintered into separate camps of owners, engineers, and contractors, who have lost the old objective of creation and have, under the guidance and control of the lawyers, substituted two new primary objectives: 1. To protect one's own skin. 2. To detect and punish culpable negligence of one of the other parties. This process has become so ludicrous that a number of thoughtful observers from all of the camps (including even some lawyers) have come to recognize that there must be a better way to undertake construction works than to use them as wrestling arenas. The road to improved contracting methods starts with mutual understanding of each other's problems and viewpoints. To this end, discussions such as this RETC session make a useful contribution. To

Jan 1, 1983

The United States is rapidly depleting many of its most important minerals and fuels. The first two Annual Reports by the Secretary of the Interior, under the Mining and Minerals Policy Act of 1970, made us acutely aware that the natural resources that enabled this Nation to attain an unprecedented growth in terms of economic well-being, and to set an example of independent strength through the democratic process, are finite. Once they are depleted, large imports will be required. Simultaneously, competition for available supplies, especially of petroleum, is increasing in the expanding European and Japanese industrial communities and in the underdeveloped nations of the world. Even before the crisis of late 1973, the oil-producing nations of the world, principally in the Middle East, but including Canada and Latin America, were recognizing that the worldwide need for crude oil, petroleum products, and natural gas could be translated into an unprecedented economic bargaining position. Thus, the members of the Organization of Petroleum Exporting Countries (OPEC) raised the price of their crude twice during the first 6 months of 1973. By yearend the energy situation had be-come acute, and it seemed probable that regardless of current political developments, the era of cheap energy was over.

Jan 1, 1973

By Raymond B. Ladoo

Talc is a hydrous magnesium silicate having the chemical formula H2Mg3 (SiO8 ) 4 ; it is often called steatite, soapstone or potstorie, and by the trade names talc clay, agalite, asbestine, and verdolite. The term talc may be used to include all forms of the pure mineral, whereas steatite denotes particularly the massive, compact variety, and soapstone the impure, massive form that often contains only 50 per cent of talc. Merrill 1 says: The name soapstone is given to dark-gray and greenish talcose rocks, which are soft enough to be readily cut with a knife, and which have a pronounced soapy or greasy feeling; hence the name. Such rocks are commonly stated in textbooks to be compact forms .of steatite, or talc, but as the writer has elsewhere pointed out, and as shown by the analyses here given, few of them are even approximately pure forms of this mineral, but all contain varying proportions of chlorite, mica, and tremolite, together with perhaps unaltered residuals of pyroxene, granules of iron ore, iron pyrites, quartz, and, in seams and veins, calcite and magnesian carbonates. When pure, talc is soft, having a hardness of 1, but when impure or when it grades into its varieties, the hardness increases to 3 or 4. Talc ranges in color from pure white and silvery white through gray, green, apple green, gray green to dark green, nlso yellow, brown, or reddish when impure. It is rarely, if ever, found in wellformed crystals, but often occurs in foliated plates or in fibrous aggregates. It is commonly compact or massive or in fine granular aggregates. Several analyses of talc from different regions ·are given in Table 1. Talc has several varieties, the most important of which is Rensselaerite. This variety, found in a small area near Gouverneur, St. La.wrence County, N. Y., is a hard, fibrous, -waxlike mineral having the same chemical composition as talc, but lacking its softness and its peculiar greasy feel. Its hardness and its peculiar fibrous form, even when ground, have made its grinding and separation a separate problem. In addition to the varieties of talc and soapstone, the mineral pyrophyllite or agalmatolite, a hydrous silicate of alumina, with the formula H2Al2 (Si08 ), is also mined and sold as talc. It resembles talc in color, feel, luster, and structure, and may be successfully substituted for true talc for most uses. In this paper it will be considered as one of the commercial forms of talc.

Jan 1, 1923

By W. R. Crane

Mining of the red iron ores of the Birmingham district, Alabama, has _gone on energetically for the past 50 years and has created a large iron and steel manufacturing center, the only important one in the South. The district produces about 10 per cent of all the iron ore mined in the United States and 80 per cent of the Alabama output is red ore ; moreover 43 of the 419 blast furnaces of the country are in the district tributary to Birmingham and produce 7 per cent of the pig-iron output. The rapid growth of the district has been made possible by investigations that have led to radical changes in furnace practice; studies of methods by which the low-grade, highsilica ores may be treated by concentration 1 will give still greater impetus to development. The· mode of occurrence of the ore has made mining practice comparatively simple, but with the rapid extension of the workings underground and the disturbed condition of the ore bed some distance from the outcrop, conditions tend to become more difficult. Stoping, handling, support, drainage, and ventilation are all affected, sometimes favorably and sometimes adversely, by the extended workings and increased depth of cover. Should beneficiatioil make available the high-silica ores of the lower bench of the Big Seam, mining practice must necessarily be adapted to the new conditions and will be rendered more difficult as the weight of cover increases at long distances from the outcrop. The support of workings will require more attention as the weight of cover increases, and the efficient and economical operation of the mines will depend largely upon improvements in mining and handling the ore.

Jan 1, 1927

By D. Jamróz, A. Surowiak, T. Niedoba, P. Pieta

"The separation of coal material of three types of coals originating from three various Polish hard coal mines (types 31, 34.2 and 35, according to Polish nomenclature, which were steam coal, semi-coking coal and coking coal) into particle size fractions and then into particle density fractions was done and then the following parameters were measured for each particle size-density fraction: combustion heat, ash contents, sulfur contents, volatile parts contents, analytic moisture. In this way a 7-dimensional vector of data was created. Using methods of factor analysis the important features of coal were selected, which decide about their membership to individual types. To evaluate the appropriateness of the applied method the Bartlett’s sphericity test as well coefficient of Kaiser-Mayer-Olkin (KMO) were used. To select important factors the Kaiser criterion and Cattell’s scree test were used. The obtained results were compared with the results obtained in previous works by means of observation tunnels method. The results showed which particular features are crucial to define the type of coal what is also important to select appropriate method of its enrichment.INTRODUCTION Coal extracted from the mine is often a mixture of coals of various quality originating, for example, from various coal layers. One of the most important issues is to determine its quality, what means to verify if it fulfills certain requirements. Usually, such parameters as combustion heat, ash contents, sulfur contents, volatile parts contents and analytic moisture decide what the coal quality is (Drzymala, 2009). Such investigations are expensive and time consuming. That is why it seems to be important to determine the mutual connections and interactions between them what would make possible to reduce the amount of the necessary parameters. This issue was already investigated with successes in several works [Jamróz and Niedoba, 2013; 2014; Niedoba, 2015]. This work is another approach to this problem. Here, the investigation of possible reduction of researched parameters was done on the basis of the factor analysis. The obtained results confirm the earlier observations."

Jan 1, 2018

By J. Fox, K. Kocsis

"Planning for sustainable cooling potential requires protected space to successfully maintain chilled propylene glycol in storage until needed. Stored propylene glycol should be judiciously cared for, safely kept from the ill effects of heat, in order to remain useful for bulk air cooling. Minimizing the chilled temperature of the propylene glycol reservoir tanks means that atmospheric conditions will be monitored closely during the chilling phase. Storage facilities would maintain restricted airflow while minimizing possibilities for heat transfer during the storage phase. Sustainable cooling systems could reduce or eliminate the need for mechanical cooling if installed with favorable conditions. Storing the cooling potential from the winter months is what this new design is all about.INTRODUCTIONIn most subsurface, bulk air-cooling methods, the main source of potential cooling energy comes from cold-water applications. This paper investigates the practical use of harvested, chilled propylene glycol as the source of cooling potential. Propylene glycol is chosen as the cooling storage liquid refrigerant since its chemical make-up is intrinsically safe to fresh water supplies and will not harm underground workers should a leak occur in the closed cooling circuit. Harvesting the cold of winter is a meaningless endeavor without proper thermal planning for the storage of the cooling potential in cold refrigerant.PROPYLENE GLYCOL STORAGE RESERVOIRA new design for a closed refrigerant bulk air cooling system employing propylene glycol as the refrigerant is presented as the main design topic of this paper. Given that a deep and hot mine will need to be considered safe and productive, a cost-effective cooling system is desired in order for the mining operation to be considered sustainable. For underground mines at northern latitudes, cooling applied to fresh air is only required 3 to 4 months of the year. During winter, ambient atmospheric conditions can be harnessed and stored for use at a later time.The basis of this sustainable design uses very cold ambient air that is circulated around galvanized steel refrigerant reservoir tanks. The propylene glycol reservoir tanks are arranged in a concrete walled pit, or tank farm, excavated in bedrock. During the coldest months, the tank farm will be exposed to the open air. As the seasons change the tank farm will be covered with insulation to maintain the maximum cooling potential for use during the warmest months of the year."

Jan 1, 2019