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By G. F. Weaton

1.1 The purpose of this paper is to show the way by which estimates are made of the tonnage and grade of iron ore and taconite reserves of Minnesota. 1.2 The procedures include those of estimating the open pit reserves of: (a) Natural iron ore, and (b) Taconite 1.3 The methods of estimation which will be discussed are primarily based on the information from exploring iron ore deposits. They consider the geology of the deposit as well as the contained mineral of potential value. 2.0 Some geologic, engineering, and economic principles. 2.1 Ore 2.11 "In the broad economic sense, and from a legal standpoint as well, ore is mineralized rock, which under appropriate conditions of time, space, technology, economics, and politics, can be mined, processed, and made to yield a saleable metal , or other mineral products at a profit."(Parks, 1957) Stated differently, metallic ore is rock material from which presently known methods of beneficiation, a merchantable concentrate, suitable for use in the manufacture of metals at a profit, can be produced. Crude ores as low as 0.38% metal, as in the case of copper and even lower in the case of the precious metals.

Jan 1, 1985

By R. B. McCammon

Four areas have been identified as favorable drill-site locations for determining whether or not a suspected prophyry copper deposit exists in Rowe Canyon, Nevada. Favorability is based on the similarity to a deposit model constructed from geochemical data for the porphyry copper deposit near Ely. Favorability is defined as the coincident number of positive anomalies for the elements zinc, silver, arsenic, antimony and iron. The favorable areas coincide with an observed magnetic high and areas in proximity to major faults.

Jan 1, 1979

By Roberto de Moraes

Lunar construction faces unique challenges arising from the nature of regolith and megaregolith. Unlike terrestrial soils shaped by weathering, lunar regolith is composed of angular, poorly sorted particles produced by impacts, with bulk Density, strength, and trafficability varying sharply with depth and terrain. Boulder fields, floaters, and talus aprons add further complexity, disrupting excavation and mobility. Apollo missions documented these conditions through drive-tube samples, trenching, penetrometer data, trafficability tests, and seismic profiling, but the results remained as datasets rather than a unifying classification. This paper introduces the LRC (Lunar Regolith Classification) Framework and the Overconsolidation Ratio applied for the Moon (OCR*), the first contractor-ready system to organize Apollo-derived trends into excavation demand zones (L1–L5). LRC is explicitly a classification, not a stratigraphy: depth ranges are indicative and require in-situ verification before use. Each zone is defined by bulk density and strength ranges, field proxies (bootprints, trench stability, auger torque, seismic contrasts), and corresponding excavation implications. Worked examples from Apollo 15 (mare), Apollo 16 (highlands), and Apollo 17 (pyroclastics and talus) demonstrate how observed data translate into LRC zones. These cases show that LRC captures both systematic depth trends and sharp local heterogeneity. The framework standardizes excavation planning for landing pads, haul roads, berms, foundations, and tunneling trials, while converting floaters from hazards into resources. LRC thus provides a common language for lunar construction. Rooted in Apollo evidence but designed for Artemis verification, it is proposed as a living standard; a reference framework to guide site preparation, excavation, and risk management in the next phase of lunar development.

Feb 22, 2026

By D. S. Bubar

This presentation will represent a diversion from the central theme of Cordilleran geology, in both time and space, as we move 2,000 miles east of Spokane to eastern Canada, specifically the province of Quebec, to discuss a major new Archean-age volcanogenic massive sulphide deposit called Louvicourt. The deposit is located in the Val d'Or camp in the prolific Abitibi Greenstone Belt some 400 miles north of Montreal. It was discovered by Aur Resources in June, 1989 on a property operated under the terms of a joint venture with Louvem Mining, a Quebec company controlled by Ste. Genevieve Resources Inc. of Montreal. As a geologist, I am proud to be able to describe Louvicourt as a geological discovery, as it was found by doing systematic deep diamond drilling based on a geological concept. The deposit is essentially blind from surface and lay undiscovered for the 10 years that the Louvem mine was in production just 2,000 feet away from its easternmost workings.

Jan 1, 1991

By D. N. Madge

A description will be given of an approach to plant process automation based on the strategy of first developing an information system followed by later development of process models. The advantages of this approach over the unit process control will be outlined. Some insight will be given into the risks associated with this method. These risks can be shown to be primarily economic.' Some reference will be made to two Cominco installations in the interests of illustrating the generality of the information systems approach.

Jan 1, 1972

By Gary Nash

While there could be as many directions on regulations as there are viewpoints surrounding the asbestos controversy, there are a few basic criteria that generally will influence government thinking, namely: - their definition of the problem to be regulated, - their interpretation of the scientific evidence available to them, and - their sensitivities to the views of, and the implications for, various interest groups in society. Clearly, different assessments of these criteria by various governments will lead to differing regulatory regimes. The consequence, of course, is a patchwork of non-conforming regulations among nations, with all that thin implies for the distortion of international trade and the unsettling of international relations. I would therefore argue that when governments are examining regulatory action, they should explicitly take into account their common interests in stable and cordial international relations, and when possible, efforts should be made to ensure that movement on regulation is at least, in principle, in accord with the general views of the international community.

Jan 1, 1984

By R. O. Y. Breese

Perlite is a hydrated acid volcanic glass that has been derived from the alteration of obsidians through incorporation of water into the silica structure. It is distinguished from other members of the water-bearing natural glass family by total water content, characteristic fracture and luster. The distribution of major occurrences worldwide is associated with silicic Tertiary through early-mid Quaternary volcanics related to plate movement. The No Agua dome and flow complex is one of the most highly studied perlite occurrences in the world. It clearly exhibits lithologic and textural zonations that reflect simple cooling history. Similar features are commonly observed within other perlitized, extrusive glass selvages. This paper briefly discusses current thought regarding geologic occurrence, the hydration process and the modes of origin with special emphasis on No Agua.

Jan 1, 1985

By Chris Lynagh, Collin Schroeder

Determining the best excavation method is a critical step in successful tunnel construction. In rock tunneling, several factors can dictate the excavation method, such as: (1) rock characteristics, (2) tunnel size and length, (3) nearby utilities/infrastructure, and (4) contractor’s preferred means and methods. This paper discusses the various rock tunnel excavation methods utilized on the Doan Valley Storage Tunnel Project (DVT), a project constructed as part of the broader Project Clean Lake in Cleveland, Ohio. The differences between each method’s initial and final lining, geology, and cycle sequence will be analyzed and compared.

Jun 13, 2023

By W. M. Tupper

[The two types of sulfide deposits in the Bathhurst Newcastle area are; (a) epignetic fissure deposits, and (b) massive sulfide deposits. Geological evidence has been variously interpreted to suggest a syngenetic origin, a source bed' origin, or a magmatic hydrothermal origin for the massive sulfide deposits. Sulfides disseminated through the black shales and argillites of the host rocks are enriched in S32 (mean value 22.34, S34. = 5.8 per mil) relative to the meteoritic standard of 22.21, and have a broad spread in range of values. S32/S34 ratios of sulfide minerals from the deposits occur in two distinct groups. The massive sulfide deposits exhibit ratios between 21.88 to 22.05, while the fissure deposits exhibit ratios between 22.18 and 22.21. These results suggest two separate sources for the sulfur, each, however, resulting in magmatic hydrthermal deposition because of the narrow spread of ratios in each group. Granite intrusive into the host rocks of the sulfide deposits have a mean K/A age of 386 ± 10 M.Y. Lead minerals in the sulfide deposits have a mean nodel lead age of 370±20 M. Y. Thus the lead minerals and the granite bodies were emplaced during the same major orogenic event. Sulfide minerals from magmatic hydrothermal deposit have a very narrow range of S32/S34 values, as do those of the Bathurst area. It seems reasonable, therefore, that well homogenized magmatic hydrothermal solutions are the most logical source of the sulfide deposits. Furthermore, the homogeneity of the lead isotopic abundance data gives strong independent evidence that the ores are of a magmatic hydrothermal origin.]

Jan 1, 1960

By Denis Tepavac, Mark Trim

Structural performance of fiber reinforced concrete (FRC) depends on its ability to carry tensile forces after cracking. Australian Standards AS5100-2017 and AS3600-2018 are the only available design standards that establish a test procedure to determine strength and toughness of an FRC in direct tension. Direct tensile testing of fiber reinforced shotcrete samples was performed to determine if the model and guidelines in AS5100/3600 were applicable to shotcrete; all previous testing was from cast samples. In addition to direct testing, micro CT-scanning was also performed. The paper presents tests performed, results, and how the tests could be used on future projects. In addition, a brief summary is provided of the guiding structural mechanics used for estimating residual tensile strength and test methods utilized to verify those estimates.

Jun 13, 2023

By Kaixi Jiang, Chaozhen Zheng, Shuchen Qin, Hao Ma, Yufang Wang

The study investigates the behaviors of zinc and iron in neutralized residue during pressure and hot acid leaching. It examines the effects of temperature, acidity, leaching time, and oxygen partial pressure on zinc extraction. The results indicate that the acid to zinc mole ratio is crucial for the extraction process, with a zinc extraction rate reaching 98.0% under optimal conditions.

Feb 14, 2022

By Frederick T. Graybeal

Silver Bell is located about 56 km (35 miles) northwest of Tucson, AZ. It is a classic porphyry copper deposit containing enriched disseminated chalcocite ore in altered porphyritic rocks with chalcopyrite in adjacent skarn zones. The discovery of Silver Bell was an evolutionary process that occurred over a 75-year period. Recorded mining activity began about 1865 on Boot Hill east of El Tiro pit (see Fig. 1) where outcrops of altered limestones were found to contain 425 to 482 g (15 to 17 oz) Ag mixed with copper oxides. By 1874, the Young America Copper Co. was mining shallow occurrences of 30% Cu along the north side of the present Oxide pit. The ore was shipped by wagon to Yuma, AZ, and then by boat to San Francisco for smelting. By 1881, the district supported several mining companies, two small smelters, and was being favorably compared to Bisbee in local newspapers. Most of the ore mined in the period 1865-1903 came from pods of massive sulfide or their oxidized products which were distributed in an unpredictable fashion through a large skarn zone in Paleozoic limestone east of El Tiro pit. Ore grades varied from 5 to 10% Cu.

Jan 1, 1991

By Kirk L. Prather

Why discuss techniques of accident prod lot on? Would it not be more useful to discuss means to reduce accidents? This discussion will answer these questions by suggesting ways in which effective accident prediction techniques improve the ability to foresee and prevent accidents. Accident Prediction Process The secret to accident prediction is to utilize the tendency for history to repeat itself. The same circumstances and the same human behavior that produced accidents in the past tend to produce accidents in the present and the future. The ability to predict accident occurence in the future by projecting from the past is a statistical process. In a bookmaker's jargon this means "playing the odds" or "the percentages". A horse or a sports team may be beaten on any given day, but by skillfully assessing the factors of past performance and assigning odds, many clever bettors make money in the long run.

Jan 1, 1973

By A. Nieto

Rare earth elements (REEs) are crucial to green technology such as hybrid-electric vehicles, wind turbines and fluorescent light bulbs. As of 2011, China dominates the global production of REEs and is reducing its export quotas. To predict the supply of rare earths in the United States based on future supply scenarios, a web-based database and geographic visualization tool was built. Five case scenarios with varying levels of REE demand were created by varying several economic conditions including (1) international trade policy, (2) greenhouse gas regulations, (3) environmental mining regulations and (4) tech applicability ratio of REEs. The most likely scenario, which is based on current international demand levels, indicates the importance of expediting the development of extractive operations of current REE resources within the United States. The results of the different case scenarios are supported by using dynamic geographic maps indicating the location of rare earth ore (REO) resources.

Jan 1, 2012

An incremental-analysis-based stope design and cutoff grade calculation method was developed for an underground metal mine project. Traditional stope design methods are typically very time consuming and lack consistency and accuracy by manually drawing stope shapes. For quick reserve calculation and economic analysis, a new method named "3D incremental analysis based stope design" was created for mine-wide stope designs. The key idea of this method is to replace engineers' manual checking of each incremental ring with one calculation of all the rings, and to build the final stope shape with the maximum values. This process was realized through a 3D ring grid setup and proper naming conventions for rapid calculations. With this unique but practical method, multiple options for a mine design were completed within a short time before the final selection of optimal cutoff grade and best stope designs for the project.

Jan 1, 2012

By Michael J. Hannan, Thomas F. Torries

The nature of industry structure is examined and the structure of the aluminum, copper, lead and zinc industries are described by the use of factor analysis. Capacity is defined and the relationship between industry structure and capacity utilization is examined. It is demonstrated that excess capacity is possible in industries with competitive or monopolistic characteristics, but the effects of the overcapacity are vastly different in the two cases. In a competitive industry, cycles of overcapacity with attendant fluctuating prices are expected. A change in industry structure from monopolistic to competitive characteristics over time causes profits and economic rents to be transferred from the producer to consumers of the mineral.

Jan 1, 1989

By Roger Escoda Estelrich, Joan Carles Casado Ortega, Mitchell Gerdau, Jose Raul Martinez, Jeb Pittsinger, Frank Perrone

The existing Chesapeake Bay Bridge-Tunnel complex is being expanded to include the Parallel Thimble Shoal Tunnel. This will be a subaqueous bored crossing between two islands constructed for the original 1960s immersed-tube tunnel. Jet grouting was employed by the Chesapeake Tunnel Joint Venture (CTJV) to provide watertight base plugs, launch and retrieval blocks for the tunnel boring machine (TBM), a TBM canopy to limit ground movement, and a retaining wall to enable off-island excavation: all within hydraulically placed sands. This paper will review the design and construction challenges, including soil permeability and recharge, grout communication, installed grout strengths, and remediation requirements.

Jun 23, 2024

By T. B. Thompson

The Cripple Creek diatreme-intrusive complex is known primarily for its vein telluride-gold ores and, for major veins, their great vertical range (>990m). Less well-documented are the ores dispersed into the wallrocks adjacent to veins, the ores associated with hydrothermal and tectonic breccias, or mineralized zones within fluvial, lacustrine, and volcaniclastic rocks deposited within the diatreme complex. The ore-gangue minerals Here precipitated from oxidized, alkaline fluids that yielded an abundance of carbonate, sulfate, and oxide minerals along with minor base metal sulfide and precious metal telluride-s. Wallrock alteration is quite limited adjacent to veins and somewhat more extensive within hydrothermal and tectonic breccias.

Jan 1, 1991

By D. W. McGlashan

[Becaune ad ;the extennive nwrgace anea od u.X chopRex2 in emmiom, emuhion dRokdtiun oddeh poaaibWa don ;the necove/ry ul; BinQey divided minmcd pa~LL&a, Swr~aC;tavu% mu2 akab&ze ;the emu-bion and poan an an ad~i&y don ;the dahed mina&. OZhm hpohtant acto oh me ;the naAwre od ;the em&iun inghedied, ;the nQRaLLve volwna 06 the colz;tinuoun and dincon;tinuoun phaa, ;the change aign bonne by the dnuplm ad the o.X phae, ;the z&a pu;tenticd od ;the dahed minmd, the ~olubRe am curdent 06 khe wcr;ten-pulped and gnuund onu. AX on nem ;the AoQRec;trtic point on ZPC, ;the doubRe Raym about ;the minW-&den oil dnopR& i~ neduced in ;tkichnaa and the dn_opR& wU codace and continue to aggnegate into agglommaka . Invetmion dnom O/U ko W/O can UCCWL depending upon a nwnbm a 6 in;tmQeaked daotuh~. EReothokin&Lc inn&wnenta;t/iun to meanwre ;the ZPC, QReckProphonQkic mobilXty z&a pokeW and hakerning cuttrtent me invcduabte in ;the appficatiun ud emu-bion dRo;tat;iun ;to m&~c and nonm&~c minu.&. ] INTRODUCTION Recent interest in emulsion flotation can be ascribed to the necessity of selective separation and concentration of extremely fine minerals. That which follows is an elucidation of the many factors-in emulsion technology in application. In applied surface chemistry for solid-particulate separation and concentration, emulsion flotation is one of the intermediate processes between froth flotation, in which the continuous phase is water (99.5 to 99.999% by volume), and particulate extraction, in which the continuous phase is almost entirely an organic-fluid. Another intermediate process is particulate exchange (or partition) in which immiscible or very limitedly miscible phases are in controll¬ed but appreciable volumes. Surfactants are common to all of these

Jan 1, 1968

By Erica McGlynn, Brian Negrea, Lance Jackson

There was no need for the people of Cleveland to ask “Where does the raw sewage go? We want to know!” because it was clear. The raw sewage was being discharged into Lake Erie during heavy rainfall events due to the outdated design of the combined sewer system. In efforts to resolve this ongoing issue for the City of Cleveland, the Northeast Ohio Regional Sewer District developed Project Clean Lake in collaboration with the US EPA. Project Clean Lake is a 25-year, $3 billion program consisting of seven large-diameter CSO storage tunnels to be constructed beneath the city’s existing infrastructure. The first four tunnels have been completed using traditional hard rock TBM excavation methods. The fifth tunnel, the Shoreline Storage Tunnel Project, presents unique challenges and complexities as it will be the first large-diameter EPB TBM to dig under the City of Cleveland. The project itself consists of one tunnel drive 14,100' (2.7 miles) in length, two pipe jacking tunnels, three large slurry wall shafts, two diversion structures, and three regulator reconstructions. Upon completion of the project, 12 permitted CSO locations along Lake Erie will be taken offline, reducing overflow volumes by approximately 350 million gallons per year. This paper will discuss the current status of construction and the chosen means and methods, including the myriad of nuanced differences between hard rock and EPB TBM tunneling methods. Particular attention will be given to the site preparation, setup, and organization; TBM assembly; and TBM launching practices.

Jun 13, 2023