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By S Zaffron, O Loffredi

A critical concern of any mining company today is its relationship with the different stakeholder groups impacted by the operational activity û communities, unions, vendors, local partners and competitors, local and federal governments, interest groups and non-government organisations. What ten years ago would have gone unnoticed, now, and even more so in the future, can drastically impact the profitability and even existence of a mining operation. This paper describes the development and delivery of a new paradigm for creating effective external stakeholder relationships. We report on the actual measurable results of an integrated and highly complex initiative led by Lonmin Plc (Lonmin) and Landmark Education Business Development (LEBD) that significantly altered the nature of the relationship with the stakeholders. Given the nature of the long-term investment required in a mining operation, any breakdowns or surprises in its relationship with external stakeholders brings with it the potential for major loss. The transformation of executive and senior management and community leadership was required to enable them to be effective in managing this complex set of circumstances.

Jan 1, 2006

By T. R. Cass

THE renewed interest in titanium, resulting from its increasing application as a structural material, has stimulated basic deformation studies on this metal. In the course of our work, we have developed a dislocation etchant and applied it to a perfection study of melt-grown single crystals as well as to a preliminary investigation of plastic deformation in titanium. The etchant, Keller's etch (21 cu cm HF, 64 cu cm HC1, 106 cu cm HNO3, and 160 cu cm H20), reveals the emergence of both grown-in and fresh dislocations on pure titanium and a-phase Ti-Al single crystals. Pits are produced only on surfaces within a few degrees of the basal plane; the more exactly parallel to a basal plane the surface is, the more distinct are the pits. The observed pit density, however, does not appear to depend on the surface orientation; the pits simul- taneously become less distinct as the misorientation from a basal plane increases. Etch times are short, a few seconds, for pure titanium; longer times are necessary for alloy crystals.

Jan 1, 1968

By Zvonimir Jam?ek

In Rudarski Institut Ljubljana (RIL), i.e. Ljubljana Mining Institute, we have developed CADRIL, a smaller CAD package which purpose is to overcome the difficulties by introducing Computer Aided Design in our mines. Program CADRIL is a graphics shell for several computer applications in mining. With the basic version of CADRIL all 2D working maps for daily use can be produced. Inserting different program blocks into CADRIL we get versions MAPRIL, TAHRIL, SECRIL and so on. The main purpose of all versions is graphics design. The main and most innovative feature of CADRIL is the screen four-word command menu. Not having pull-down or tablet menus is the speciality of this program. CADRIL contains 500 achievable commands. Each of them can be composed by choosing two to four expressions stored and shown in a specific four- column menu, sorted as objects functions, parameters and modes. Thus all commands are immediately accessible. As a result of its plainness and adaptability to the present working methods of mining engineers, CADRIL quickly attained a good reputation in our mines.

Jan 1, 1992

The most frequently applied project evaluation criteria are the Net Present Value, the Internal Rate of Return, and the Pay Back Period. Unfortunately, the Internal Rate of Return and the Pay Back Period, if interpreted according to their traditional definitions, easily produce results which contradict the Net Present Value. The reasons for the Net Present Value incompatibility of the two criteria are that these criteria have not been adequately defined and so new, complete definitions are recommended. The concept of the True Rate of Return is proposed as a substitute for the interest rate that the Internal Rate of Return has been believed to represent. The redefined Internal Rate of Return and Pay Back Period criteria, as well as the True Rate of Return are all Net Present Value compatible and can, therefore, serve as independent project evaluation criteria. Also, the correct approach to the evaluation of mutually exclusive alternatives and the status of the often neglected borrowing projects in project evaluation are found to be quite important.

Jan 1, 1991

By Robert A. Melton

Since many of the easily mined, continuous, thick coal seams in the Appalachian Region have been exhausted, new exploration and mining is being directed toward less continuous seams that are under more cover and are more difficult to mine. The direct results of this are that more money and time and more expertise and data are needed to plan and open new coal mines today. It is also becoming apparent that the old methods of assimilating and preparing information needed for mine planning are inadequate to meet the needs of today's modern mining engineer, especially in the areas of data gathering, storage, retrieval, preparation, and interpretation. The system described here allows assimilation of old and new core data in a relatively quick, accurate, and efficient manner. The system is a set of computer assisted procedures consisting of the following four basic steps: 1) raw data collection, computer input, storage, and graphic preparation, 2) geologic profile correlation and establishment of seam continuity, 3) computerized data posting of important seam parameters, 4) geologic and planimetric analysis for mine planning.

Jan 1, 1977

By Mark A. Ackerson, Kenneth E. Hjelmstad

An ideal fire warning alarm system for underground mines would be low cost, convenient, fast, reliable, and able to warn all underground workers. Present warning systems, such as phones, messengers, and stench, fail one or more of these criteria. The U.S. Bureau of Mines may have devised the ideal system. The one way communication system employs a large loop antenna and transmitter to create a 630 hertz (Hz) electromagnetic field to send information through-the-earth to cap lamp battery mounted micro- receivers worn by underground miners. Field tests of prototype equipment in 1986 resulted in through-the- rock signal transmission of over 762 m (2500 ft). Subsequent hardware upgrades for more recent tests resulted in transmissions of over one mile. Recently developed receiver circuitry employs phase- locked-loop detection circuitry responsive only to a specific series of pulses of given time duration, that eliminates false alarms from electromagnetic noise emitted by mine equipment, power lines, or lightning. A multichannel system can relay standard messages to miners

By D. Harris, M. Osterberg

This paper examines the economics of acquiring mineral exploration rights by royalty-rate bidding when the royalty basis does not provide for full cost recovery. Bidding takes place prior to exploration and the documentation of actual tonnage and grade. Consequently, it increases considerably the risk to exploration capital when the fraction of cost recovered is small and the product price exhibits large fluctuations. Price and grade risk are demonstrated on a 360-Mt (400-million-st) porphyry copper deposit by Monte Carlo simulation of discounted-cash-flow analysis. Copper price is modeled as a stochastic price process, and costs are based on US Bureau of Mines cost models. When both grade and price risk are considered, the probability for a negative NPV is 0.54, given a royalty rate of 5% applied to a basis that allows the recovery of costs up to 50% of product price. Investment risk could be considerably reduced by defining the royalty basis to allow greater cost recovery. Although such a basis would require society to share in the risk, society would benefit from greater resource development.

Jan 1, 2000

By Christina Graf

A synthesis of colloidal gold shell particles with a silica core is described. Small gold nanoclusters were attached to the functionalized surface of colloidal silica particles. Reductive growth and coalescence of these clusters lead to the formation of a closed gold layer. By variation of the thickness of this gold layer and the radius of the shell it is possible to adjust the plasmon resonance of the gold shell particles over the whole visible and infrared region of the spectrum. The optical properties of the particles made are in good agreement with theoretical calculations for coreshell particles. Due to their low polydispersity these gold shell particles form in solution large crystals with submicron lattice constants. It is also possible to produce hollow gold shells by dissolution of the silica core. A new method to coat the silica core gold shell particles with an additional outer silica shell is also presented. This allows due to a reduction in the Van-der-Waals forces to make more permanent dried crystals and facilitates functionalization of the particles for use in various photonic applications.

Oct 1, 2003

By Vas P. Srinivasa

A comminution circuit is an important integral part of a mineral processing plant. Nearly 40% of the capital cost and 30 to 40% of the operating cost are taken up by the crushing and grinding circuit. Therefore, considerable care should be given to the design and selection of this circuit. Several factors affect the selection of a comminution circuit--energy consumption, avail- ability of the equipment, the remoteness of location, and availability of trained personnel, to mention a few. Each of these factors influences the choice. Selecting a comminution circuit strictly on lower capital cost may not be optimal. Crushing and grinding circuits are usually site specific and should be selected - only after careful analysis of all the factors involved. The objective of this paper is to show the effect of these factors, which are extranious to capital cost. Usually, the capital cost of a semiautogenous grinding circuit is lower than that of an equivalent conventional circuit. However, due to lower equipment availability and high power costs in certain locations, the economic advantage of lower capital cost is lost. Analysis indicates that a break even point occurs at a power cost of 5¢/kWh. This paper describes the procedure utilized for selecting the most economic comminution circuit and states the conditions applicable for each cominution circuit.

Jan 1, 1983

By L. F. Contreras

In open pit mine design, it is customary for geotechnical engineers to define the appropriate slope design angles within practical limits. The conventional approach to slope angle design is based on the comparison of calculated stability indicators, such as the factor of safety (FS) and the probability of failure (PF), with generic acceptability criteria not directly related to the impacts of failure. A major drawback of this type of approach is related to the difficulty of defining meaningful acceptability criteria. An alternative methodology of pit slope design is proposed, where the economic impacts of potential slope failures are calculated and used as the elements on which to apply the acceptability criteria for design. The methodology is based on the construction of a graph, referred to as a risk map, that relates the probability of exceeding the economic impact of slope failure to the magnitude of the impact measured in monetary terms. The process includes the analysis of a selected number of representative years of the mine plan and slope sections of the pit areas to define the required inputs for the construction of the risk map. The paper discusses the concepts used in interpreting the probability of slope failure, and describes the approach followed for the estimation of the economic impacts of slope failure and the construction of the risk map. Finally, the two main uses of the risk map are discussed, including the comparison with acceptability criteria for the evaluation of a specific open pit design and the comparative analysis of open pit design options in terms of value and risk to identify optimum pit layouts.

Jan 1, 2015

By Rowlands N. J, Zimmermann D. O

The Engel Model search simulator is described with particular emphasis on preparation of input parameters. The computer has a "black box" role in the same way a telephone or radio is a "black box" in communications. A search technique (sensor) is selected and applied in two stages of'search, namely, reconnaissance and detailed. The model relies on knowing and quantifying the parameters of the target sought and the search technique; this is usually done by analogy studies from available literature and experience. The parameters are then balanced by feasibility studies on the search area. Case histories show that the study makes the user aware of what he is likely to find rather than what he wants or needs to find to be viable. Two case histories are presented: one for Mississippi Valley type lead- zinc deposits and another for stratiform copper. The first study showed particular benefits in the input stage and highlighted the fact that one could expect a lot of encouragement by way of interesting results but with little chance of finding the high-grade,

Jan 1, 1974

By W. R. Webb, M. O. Peterson

WHEN men drive haulage equipment ranging up to 22 tons in an open pit operation, they must live with the realization that their safety is dependent upon the machines they drive and how well they operate them. The hazards inherent in their jobs must be recognized, met, and defeated. It comprises a never ending struggle toward perfection-an almost un- obtainable goal. The Jones & Laughlin Benson Mines, at Adirondack State Park in New York, created a safety program which resulted in only one three day lost time accident from April 1948 to April 1952. At the very start of the program, management of the open-pit operation recognized the hazards existing at Benson. The program was designed to meet each danger. With a knowledge of the problem faced, the process of minimizing each facet was planned along lines of maintenance of equipment and training of personnel. Its success is evident. In the ever-present struggle, care and maintenance of machines and application of experience to new equipment design are mainstays. Truck Haulage Benson produced 2.9 million tons of crude iron ore and 1.6 million tons of waste in 1951. To do the job, truck mileage reached 500,000 miles. The tremendous mileage emphasized to safety planners, the fact that the more work done, the greater the possibility of risk in haulage operations. Instrumenting the aim of the safest equipment possible is a methodical servicing program. Like other segments of the drive, the servicing program is based on greater production with fewer accidents. Every truck is serviced at least once per eight-hr shift. Examination includes inspecting and tightening wheel studs, checking tires, steering apparatus, lights, brakes, wipers, heaters, fire extinguishers, and refueling. A running history of the equipment's operating life is kept in the form of service and maintenance records. Machine operators are constantly on the alert for malfunctioning of units. At the first sign of trouble the truck is returned to the garage for exchange. No truck functioning incorrectly is kept on the line, regardless of its shift check schedule. The program resulted in a reduction of the number of costly overhauls and cut down the number of haulage accidents. Miscellaneous Mobile Equipment Auxiliary units, operating within the pit, have presented definite safety problems. The highest accident rate in the pit occurred on trucks carrying water and bits to the churn mills. The weight and awkwardness of bits and drill stems, combined with remote delivery points were direct causes of numerous accidents. Here, the problem has been one of equipment handling, rather than haulage. All air compressors for secondary drilling are truck mounted, facilitating mobility. In addition to making it easier to move the equipment, truck mounting has eliminated many of the hazards connected with relocating machinery. By making air compressors independent of other units, drilling operations have been speeded up considerably. Unseen rocks in the path of moving vehicles are a constant source of tire damage. At Benson the problem has been met by supplying each loading crew with a bulldozer for cleanup operations. The pitman directs the dozer operation, and when truck drivers back into loading areas, he serves as an extra set of eyes. Modern Truck Garage Provides Drive-Through Service Simplicity is the essence of any preventative maintenance program. At Benson, a modern garage, with a drive-through service bay simplifies servicing. Shift inspection of the 22-ton haulage units is accomplished with minimum delay and maximum thoroughness. Major repair work and periodic overhauls are done in the repair section of the truck garage. Crane facilities for handling heavy assemblies ease the job and add to the safety factor. Other mobile machinery,

Jan 1, 1952

By Manfred Hager

The ability of conveyor belts to transport large mass throughputs economically over previously unprepared ground has resulted in this system achieving great and extensive use. A significant component in this development is the conveyor belt itself. The development of high strength steel cord conveyor belts involves the optimising of splice design, the use of excellent rubber material especially in the splice, good craftsmanship during splice production and modern field vulcanisation equipment. The durability of a splice for belts of class St 3000 up to St 790 is expressed by the fatigue strength under dynamic stress. The results obtained with a test method and equipment developed by the University of Hannover indicate the present state of the art in this field. Belts of high nominal strength used on inclined long distance conveyors reach splice fatigue strengths of about 3000 N/mm. The design should only exploit approximately 50% of the fatigue strength determined in the tests as maximum operating stress. IMPORTANCE OF CONVEYOR BELT SYSTEMS The use of conveyor belt technology has expanded considerably over the last decades in the bulk goods transportation sector. Because of the favourable transport costs and the technology's adaptability to specific topographies, belt conveyors frequently represent the most economic solution. When flows of goods are large, as in German lignite mining operations, where masses of up to 40,000 t/h are given, it is the only technically feasible alternative. The use of belt conveyor systems allows the sensible distribution of the waste and the production of the coal (Hager, 1981). But this transportation alternative is also suitable when the masses involved are smaller. Whereas conveyor belts were only suitable for loose bulk goods up until a few years ago, today they are frequently also used for hard rock open cast mines, e.g. in the production of copper ore. Because of the favourable transport costs it is frequently still economic to use mobile crushers with a throughput of up to 10,000 t h 6 which breakdown the large blocks produced y explosives into transportable grain sizes. In many operations, trucks are only used to provide flexibility between the excavator and the crusher, i.e. over short routes, and the long, frequently steep, transport paths to the processing plant or to the spreader are undertaken by belt conveyors (Einenkel et al., 1992). The advantages of belt conveyors, i.e. to cope with large mass flows over inclines and down slopes of up to 1:4 have resulted in this system gaining very extensive use throughout the world. The conveyors can be installed over for the most part unprepared ground with suitable vertical radii, adapted to the locally available belt material. In the process individual conveyor belts with lengths of up to 15 km, and in the underground sector with lift heights of up to 1 km, have been built and operated. This great variety of application possibilities is complemented by a limited ability to pass through horizontal curves. This can be achieved with the help of design measures on the conveyor whilst bearing in mind the characteristics of the belt. STRESSING OF CONVEYOR BELTS IN DIFFERENT TYPES OF PLANT The advantage of conveyor belts compared with other systems is also to be found in the large available service-time window, i.e. the excellent reliability and the low costs of energy consumption and maintenance. It is in particular the reliability of a belt transport system which depends to a great degree on its main component, that is the belt - in all its different types and variations. For this reason, the belt is also given the greatest attention in the development of the individual components, because it is the belt which must be designed optimally with regard to various factors. The specific properties of the conveyor belt then assert a considerable influence on the design and sizing of most other components in a

Jan 1, 1993

By Kelly BJ, Smith GA

The recommendations of a recent American report on "Better contracting for Underground Construction" are considered in relation to Contracting practices on major Australian projects by representatives Of the "classical trilogy" - the Owner, Engineer and Contractor.

Jan 1, 1976

By G. Hausen, H. Micka

"Modern signal and power electronics made adjustable-speed AC drives technically feasible and reliable and economically attractive. Cycloconverters are discussed as a proven technology for mine hoists. \IntroductionUntil rather recent technical and commercial advances in power and signal electronics, DC motors were used almost exclusively for applications requiring continuously adjustable operating speeds and torques. More recently, the significantly higher efficiency and the accordingly lower operating costs of AC motors gained importance. An effective and efficient speed control of AC motors requires the control of AC voltage and frequency. Table 1 shows typical applications of adjustable-speed AC drives.CycloconvertersOf particular interest to the mining industry are cycloconverters for hoist drives. The cycloconverter represents by far the simplest, most efficient and most economical means of converting a constant-voltage, constant-frequency supply into an adjustable-voltage, adjustable-frequency supply as required for the speed control of AC drives operating in the frequency range to half of the utility frequency.Cycloconverters feeding synchronous motors or induction motors are ideally suited for slow-speed direct-coupled drives."

Jan 1, 1988

By J. F. Myers, F. M. Lewis

IN the mining and handling of sulphide ores, some degree of oxidation takes place on the sulphide surfaces, which are exposed to the atmosphere. It is, moreover, well known that the oxidation compounds formed are a factor when such ores are subsequently treated by flotation. Modern operating technique and reagents are capable of contending with this condition to a major degree, provided that the proportions of the reagents used are varied correctly. This is particularly true at the Tennessee Copper Co., where the ore treated contains pyrrhotite in addition to other sulphides. A number of soluble salts, some of which are unstable, can be formed during the oxidation of the sulphide ores. Those unstable salts, whose oxygen requirements are unsatisfied, are constantly changing to more stable forms because oxygen reacts with them during the crushing, grinding and other operations of ore preparation. We add no chemicals of any kind to the ore pulp in its preparation for flotation feed. Consequently the only compounds that are present in the flotation feed are those produced by the natural oxidation of the ore in the presence of air and water. The Tennessee Copper Co. ore is composed of from 60 to 70 per cent sulphides and from 40 to 30 per cent nonsulphide material. It is not the purpose of this paper to discuss the nature of these various oxygensulphur compounds nor their effect on flotation, but to describe a method for [ ] correcting the effect. Suffice it to say that we have found that the reducing sulphur and oxygen salts have a depressing action on our bulk flotation process.1 From long experience we find that the best means of correcting for this variation in our work is to increase or decrease the quantity of xanthate, the promoting agent, as the quantity of the reducing salts increases or decreases. It was, therefore, very desirable to provide the operators with some quick and

Jan 1, 1946

By Tom H. W. Loomis

The department of the Interior is a federation or holding company of several fiercely independent bureaus which have either jurisdiction or expertise - or both - in a wide range of environmental fields. Each bureau is an advocate for its own concerns and an enforcer of its own mandates. This can be confusing to the company operating in the field. I will try to explain our concerns, help you see where we are "coming from," and give you some insight as to how we can help you. Other speakers have stressed the environmental concerns and site selection factors for uranium wastes so I will focus on the concerns of the Department of the Interior and some of the assistance we can give you in this area People are more aware and more concerned about environmental factors now than they used to be. Thus the past decade has brought about an evolution in both siting and design of uranium mill tailings ponds. Site selection criteria used to be simple - find a tract of land as near to the ore supply as possible with enough space and suitable topography for the expected volume of wastes. Site selections in the past have left a legacy of problems to be corrected - radioactive wastes on stream banks and in floodplains, mill wastes in and near established communities, and unprotected wastes subject to constant erosion. This is no longer acceptable environmentally or socially to a newly aware and concerned public. (Series of 30-35 slides showing uranium mine and mill wastes in Western United States. These illustrate environmental problems, reclamation and environmentally acceptable sites. The first group of slides are aerial shots taken in Wyoming and shows a surface mine and mill area. In the various views the pit, overburden piles, mill, and tailings pond can be seen. The next series were taken in Wyoming and New Mexico. These show various views

Jan 1, 1980

By J A. Rumball

Measuring cyanide in the leach liquors associated with high copper and/or sulfide ores is a non-trivial exercise. It is well known that copper complexes with cyanide and reduces the amount of cyanide available for gold leaching. What is not so well known is that the rhodanine end point overestimates the amount of cyanide available for leaching in the presence of copper. Sulfide ions also interfere with a rhodanine end point titration, although this is less of a problem as the black silver sulfide precipitate formed clearly indicates to the operator that something is wrong. Thiosulfate, which forms readily from the alkaline oxidation of sulfides, causes an overestimation of the cyanide available for leaching due to the formation of Ag(S2O3)-. The net result of these observations is that rhodanine is rarely of value as an end point indicator in complex solutions. It generally overestimates the amount of cyanide available, providing plant metallurgists with a false sense of security. Potentiometric titrations are generally much more capable of accurately measuring cyanide in complex solutions. The interfering effect of copper can be resolved and it is even possible to estimate the copper concentration using the inflexions associated with the titration of CN- + Cu(CN)43- versus Cu(CN)32-. Using the potentiometric method sulfide ions can be determined before the cyanide measurement is made due to the formation of AgS2, although the electrode will foul with repeated measurements. Thiosulfate can also be distinguished from cyanide with a potentiometric titration. Rhodanine and potentiometric titrations are both affected by the pH of the liquor. At pH 9.2 half the cyanide will be present as CN- and half as HCN(aq) with only the CN- being titratable. This does not hold in the presence of a buffer active around pH 9. In the presence of sufficient buffer, both the CN- and HCN(aq) are titrated. Ca(OH)+ may buffer the pH when large amounts of lime have been added.

Jan 1, 2007

By A. Kapoor

Gold mill effluents contain toxic pollutants such as cyanide (CN), thiocyanate (CNS), ammonia (NH4-N), and a variety of toxic metals. Various practical and economical technologies are in use for the removal of CN and toxic metals from gold mill effluents, however, the removal of CNS and NH4-N is challenging. The presence of CNS and NH4-N may make effluents toxic to aquatic life. The new Canadian Metal Mining Effluent Regulations will require mine effluents to be nontoxic. As a result, there is a need to develop practical and economical technology for CNS and NH4-N removal. The Mine Effluents Program in the Environment Group is presently evaluating biotechnology processes for the removal of CNS and NH4-N from gold mill effluents. The processes being evaluated are attached growth systems such as a Rotating Biological Contactor (RBC) and completely mixed suspended growth systems such as a Sequencing Batch Reactor (SBR) operating in a batch mode. The research to date at MMSL has shown that the RBC is very effective in removing CNS and NH4-N from simulated effluents. The NH4-N removal project showed that the RBC is capable of removing 0.8 g NH4-N/m2 of RBC disk area per day at an average temperature of 4.5 oC and hydraulic loading rate of 0.02 m3/m2/d. The RBC was also found to be very effective in removing CNS (feed = 200 mg/L and effluent < 1 mg/L) at 8 oC and a hydraulic loading rate of 0.02 m3/m2/d. The SBR was effective in removing CNS and NH4-N (generated from CNS degradation) at SBR operating conditions of two-12 h treatment cycles and a temperature of 12 oC. The end product of CNS and NH4-N oxidation was NO3-N, which is relatively non-toxic.

Nov 1, 2002

By Noel Stearn

WHEN the Age of Machinery was suddenly thrust upon civilization about the beginning of the 19th century, an unprecedented demand for mineral resources sprang up. This demand brought about the rapid development of the known ore deposits and the discovery of such other deposits as could be encountered by energetic and canny prospectors. Thus in the countries now reasonably accessible nearly all orebodies have been located except those which are totally concealed even from the eyes and "senses" of experienced and expert prospectors. The high rate of exhaustion of known ore deposits and the necessity of looking farther and farther ahead for raw materials as a matter of insurance on the stupendous capital outlays involved in mining, development, and conversion operations, have resulted in exceptional activity in three different fields of effort. The first is purely geographic. Prospectors are now penetrating the few hitherto inaccessible regions in the hope of stumbling upon exposed ore deposits or locating visible indications of their presence. The second is chemical. Industrial chemists and metallurgists are seeking to facilitate the exploitation of lower grade ores or to find methods of recovering valuable metals from common substances. In the third field of effort lie the activities of the economic geologist and the mining engineer, who endeavor to locate concealed ore deposits which would remain hidden from the prospector no matter how expert or conscientious he might be. Obviously the task which such a man must face is both exacting and indefinite, and the tools which he has heretofore been permitted to bring to it are, for the most part, abstract-a knowledge of certain fundamental principles and processes involved in the origin, occurrence, structure, and distribution of deposits of natural resources and of the rocks which form the environments of those deposits; and a process. of reasoning by analogy supplemented by the use of the diamond drill, or such artificial exposure as -the test pit, trench, shaft, or tunnel.

Jan 1, 1928