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By J. A. Singmaster

A REPORT that it did not pay to use present-day galvanized iron on account of the short life of the material, accompanied by proofs of the state-ment in the form of a tabulated history of the first costs of various kinds of building materials and their main-tenance expense, started an investigation of modern galvanized products. At the very outset it was apparent that our experience with galvanized products was by no means unique. Correspondence with the State Agricultural Depart-ments, the Agricultural Experiment Stations, the County Agents and State Granges all over the United States brought a mass of complaint on this same score. Visits to large buyers of galvanized sheet and wire revealed the same condition coupled with an ever-increasing use of substitutes for galvanized iron. We believe, therefore, that the title of this article is fully warranted by the experience of the consuming public. A study of the proceedings of the various societies having to do with the testing and use of sheet iron and steel products revealed a tremendous amount of work on the life of the base metal itself. Great stress was laid on differences in life of various types of iron and steel, the difference amounting at best to months rather than years. Very little recent attention has been paid to a study of the life of the zinc coating and the causes of its present-day lack of durability. There have been some real exposure studies published, how-ever, which show that the weight of the zinc coating determines the protection afforded by the galvanizing, which is of far greater influence on the life than the base-metal composition. An interesting paper was published by the Phillipine Journal of Science in 1916, entitled: "Galvanized Roofing in the Phillipines," a contribution from the Bureau of Science of the Phillipine Island Government. The author, Mr. Arguelles, found on 18 old galvanized sheets, after from 30 to 35 years' exposure, from 2.3 to 4.1 oz. of zinc per sq. ft. of sheet and sums up the study by saying: Of the various factors influencing the durability of galvanized iron which have been studied with a view towards accounting for the difference in behavior of old and modern sheet, it appears evident that the greater weight of zinc per unit of area on the former accounts for the greater durability.

Jan 10, 1922

By WALTER M. DAKE

GENERALY speaking, the bituminous coal mines of the country are being operated at a loss. To purchasers of the necessary commodity, a statement of this character may have the sound of a far fetched propagandist cry; but to the coal producer who lives in the hope of an up-turn in the almost stationary market price of his product, while inking in red his monthly operating balances, it carries the ringing sound of truth.

Jan 1, 1925

The Curtin University Gold Technology Group has been involved in surveying, modelling and optimisation of batch centrifugal concentrator type gravity circuits and CIP/CIL circuits for nearly two decades. The most commonly asked question regarding gravity recovery is, “What is the benefit of a gravity circuit”, which can be hard, if not impossible, to quantify. With the help of the AMIRA P420 Project’s Integrated Liberation Leach Model (ILLM) it is now possible to evaluate the effect of gravity recovery on total gold recovery when changes are made to the grind size, gravity and/or leach/adsorption circuits. This paper demonstrates how the ILLM can be used to determine the net benefit of introducing or modifying a gravity circuit and assess the effect of operating conditions (grind size, coarse gold size distribution, leach residence time, carbon activity, etc.) on plant performance.

Jan 1, 2017

By M A. Tuck

Atmospheric air on a moisture free volume basis consists of approximately 21 per cent oxygen. The current minimum threshold for oxygen in Australia is 19.5 per cent. Atmospheric air generally will also contain water vapour and will also pick up further moisture as it flows around a mine ventilation network. This paper details the results of a study to determine how much oxygen depletion can occur due to the sole impact of increasing the moisture content of air and the potential impacts of this on ventilation system design. The study shows that the moisture content can have a significant impact on the oxygen concentration in mine air. The main factors controlling the impact are the barometric pressure, dry bulb temperature and relative humidity of the air.CITATION:Tuck, M A, 2015. What is the oxygen depletion potential of ?water vapour?, in Proceedings The Australian Mine Ventilation Conference, pp 173–176 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By Sean Hunter

Artificial Intelligence has a long history but is currently coming strongly into focus with new advancements. This leads to questions many people are asking: what exactly is AI, how can it be used effectively in mining operations, and what foundation is required to make AI implementations successful? In mining, many AI applications exist, from drill pattern optimization to predictive maintenance. However, many implementations struggle due to data integration challenges. Mining operations generate large amounts of data from many sources, such as fleet management systems, drill sensors, process control systems, and laboratory results. Unfortunately, this data often exists in silos where it’s difficult to get it out, making AI applications unable to leverage it. Worse still, tools that use AI don’t always provide their data back to the system, creating even further data silos. All these problems make it hard to take advantage of the data at the mine, slowing down and reducing the effectiveness of AI. This paper presents a comprehensive approach to organizing mining data using an AI-ready knowledge graph system. We will first explore the evolution of AI in mining, from early expert systems to modern machine learning applications. Then, we will detail how a knowledge graph can integrate business context, operational data, and AI models into a cohesive system that enables more effective AI implementations across mining operations. The proposed method has been developed considering both the unique data challenges faced by the mining industry, while also considering best practices learned from the AI field at large. By following this approach, it’s possible to better utilize existing data, getting higher quality and more complete results faster, and in a way that’s reusable and composable.

Feb 1, 2025

By S. M. Pickering, L. T. Gregg

Appraisal of industrial minerals beneath privately owned land requires a different approach and mindset from valuation of base and precious metals or energy minerals, and from valuation of government-owned mineral lands. First, is it the value of inground minerals or of mining rights that is being sought? Second, value to whom, the mining company, a potential investor, the mineral landowner, a lending institution, the property tax assessor, or a condemnor? Third, how should mineral value be apportioned between the land and mineral owner, and a mining company with limited years of lease-hold interest? These and many other questions must be addressed before a valuation method and Discount Rate are selected. For various reasons the Income Method is most often used, with Net Present Value calculations made for long term predicted mining income. Choice of an appropriate Discount Rate is critical.

Jan 1, 2000

By Ira B. Joralemon

INDIVIDUALS and small companies have discovered and brought into production the mining districts of the United States. Hardly an exception comes to mind, save for the disseminated copper properties and the great iron mines. In spite of this fine record that has made possible the industrial greatness of the country, mining by small companies and by individuals has become a vanishing phenomenon. In Nevada, the lair of rugged individualism, there are fewer operating mines and fewer miners than at any time since the 1860's. The situation in other states is nearly as desperate.

Jan 8, 1950

By GEORGE ROBERT DE BEQUE

WHAT is wrong with oil shale? The answer is of interest to the public, to the oil refiner, and to the engineer. Many people have invested in shale land or shale securities, and others would invest if early development of the industry were certain. In the face of increasing demands for oil products, oil refiners are threatened with inability to maintain present output unless the supply of domestic petroleum is supplemented. Development of the oil shale industry would open a new field for engineering services. The object of this paper is to suggest reasons why there is but one shale plant in operation in the United States, and to discuss the probable time when the business will be firmly established in Colorado. As the Colorado deposits are the richest and largest in the world, ample supply of material is assured, consequently, this discussion will be confined principally to technical problems and economic problems affecting shale development.

Jan 1, 1924

By L. A. Cramer

There are a couple of dozen junior platinum mining companies coming into existence in Southern African and most intend to mine, concentrate the PGM?s in a flotation product and sell the concentrate to one of the major producers in South Africa. The price they will receive for their product and hence the return they achieve for their investment will depend upon the large number of factors that influence the market for such a product. Unfortunately the number of buyers is severely limited as it is dominated by the two major local producers, Impala Platinum and Anglo Platinum. Furthermore the current smelting technology has limited capacity for UG2 concentrates and high nickel concentrates will quickly fill any available base metal refining capacity. Few if any overseas buyers can compete for the bulky flotation concentrate produced. This paper will explore those factors such as metal recoveries, metal prices, operating costs, capacity constraints, deleterious elements, transport issues, metal premiums and discounts that are in play, types of flotation concentrates, processing capital costs, PGM grades, etc and their impact up on what smelters and refiners might be prepared to pay for such PGM concentrates. Ultimately simple graphs and equations can be developed for probably payment terms for such concentrates. Those who negotiate well will move to the higher return section of the envelope and those who use the concentrator facilities to produce the most saleable combination of flotation concentrates will enhance their returns. A deep and firm understanding of the issues surrounding this market is necessary in order to negotiate the best possible price for the seller.

Jan 1, 2008

By L. Andrews, G. Smits, M. D. Adams, E. A. Viljoen

A new approach has been developed that is capable of ascertaining the ore component that is responsible for the preg­robbing of pregnant pulps. Many gold mines are currently treating ores containing a component that is detrimental to the recovery of gold, in that they "preg-rob" the pregnant pulp by adsorption of some of the dissolved gold. The identity of the preg-robbing component in this type of ore has been the subject of considerable debate over a lengthy period, th various suggestions including amorphous carbon, chlonte, chalcopyrite and layered silicates, such as the phyllosilicate minerals pyrophyllite, kaolinite, phlogopite and illite. A means is now available to identify and characterize the preg-robber in gold ores. This new approach consists of contacting the ore with a synthetic aurocyanide solution, identifying the mineral grains by optical microscopy and analysing each grain individually using high-sensitivity electron microprobe analysis. The approach is exemplified in this initial study by identifying the preg-robbing component in an active sample of gold-bearing shale to be an amorphous carbonaceous phase consisting of discrete particles of about 5 µm diameter interspersed with shale particles and agglomerated into grains of up to 100 µm diameter. Microanalysis of these grains as well as other mineral particles revealed that the gold content of some of the carbonaceous grains was close to 7000 g,lt, with no gold being detected in any of the other mineral phases that were found to be present (e.g. quartz, chlorite, muscovite, pyrophyllite, etc). Bulk analysis of the sample for carbon and gold confirmed that gold loadings of around 7000 g,/t would be expected if all of the gold were adsorbed onto the carbonaceous component. The carbonaceous constituent is probably also responsible for the anomalously high surface area measured for the material. It probably acts in a similar fashion to activated carbon, and the correct choice of organic blinding agent will decrease the extent of preg-robbing by lowering the activity of the material for gold, without causing any downstream problems such as fouling of the activated carbon used for gold recovery

Jan 1, 1993

By Ryan T. Smith, Anthony Sahj, Alexander T. Darnell

Every second can count when trying to board a departing flight or catch a ride-share to your final destination. Hartsfield-Jackson Atlanta International Airport is in the midst of a project that aims to cut about 13 seconds between automated people mover trains (Plane Train) that move passengers between the terminals and concourses. The project involves extending the Plane Train tunnel west from its existing terminus under the domestic terminal. Working from inside non-public areas of the terminal, Keller North America, Inc. (Keller) incorporated systems of micropile-supported steel beams and grillage to both underpin existing columns prior to tunneling and support open-cut excavation at the tie-in of the new to the existing tunnel. Dewatering aided in mining a challenging section at the start of the drive of the mixedface, sequentially excavated tunnel and an automated instrumentation system monitored the performance of the construction and its impact to the terminal. Cut and cover egress and ventilation tunnels required braced support of excavation.

Oct 1, 2022

By Douglas A. Sloan

"Recently, a number of major mining companies seemed unable to find a president from within the industry, and were searching outside the industry. From this, one could conclude that managers within the industry are either not being prepared or are not preparing themselves for presidential responsibility. Opinions were sought from a number of senior executives, to attempt to define the skills a prospective president should acquire and what actions a company could take or that a prospective president could take to acquire these skills.This paper contains summaries of the opinions obtained, along with the author's comments. The paper also describes the actions some companies are taking and the actions that an aspiring president can take to prepare himself for corporate management.IntroductionA manager is promoted up the management ladder when the manager's superiors believe that he is capable of handling a more senior position. Normally, the manager acquires this credibility by outstanding performance in his current management post, whether it be in a junior management (supervisory) or in a vice-presidential capacity.In most instances, the skills required for promotion can be acquired in the current position or, at worst, the abilities exhibited in a candidate's current role will convince his superiors that the necessary expertise for the more senior position can be acquired on-the-job. This is particularly the case when the new skills are felt to be an extrapolation of the old skills.However, in the case of appointment to presidential rank, there appears to be a need for new expertise which often is not acquired in normal management progression or, at least, boards of directors of some mining companies seem to believe this to be the case. The objective of this paper is to attempt to define the new skills that should be acquired by a manager who aspires to be the president, and to describe what actions might be taken by him to acquire them."

Jan 1, 1982

By H. Lyn Bourne

This is the fourth annual tabulation that gives mineral royalty information. The table presents previous information plus about two dozen new entries. In addition to the royalty information, some entries show the cost of purchased reserves. Last year's tabulation appeared in two issues, to accommodate all of the information. This year the format has been changed slightly so the table can be printed in one issue. This year's table presents the commodities in the same sequence as last year. Sand and gravel information appears first, followed by: crushed stone for aggregate; other stone; industrial sand; other industrial minerals; energy minerals (coal, oil shale, uranium); and finally metals. As always, a caveat relates to factors that influence the reserve values. The data should serve only as a general reference. The table is not intended to present an absolute scale of reserve costs. Several factors influence the value of mineral commodities. These factors include: • location and transportation costs (especially significant for most industrial minerals); • market conditions for both the commodity and the company acquiring the right to mine it; • quality or grade of the deposit as it reflects the amount of processing and beneficiation necessary to produce the finished product; • and legislative restrictions and conditions for mining a given material at a given site. These and other factors will influence reserve costs of reserves. The table shows the range of royalties and the variations in the basis of computing the fees. In a few instances, it gives the cost of acquired reserves based on purchase price and quantitative estimates of the material in place. The table lists the commodity; the location (either by state, US geographic area, or Canadian province); the cost (R for royalty and P for purchased cost); and the year in which the lease or purchase agreement occurred. The last column offers either comments or gives a footnote number for more information. The cost column requires more explanation. The units may refer to cubic yards (/yd), cubic feet (/cuft), tons (/T) (2000 lbs) or acres (/A). 1 cu yd = 0.76m3 1 cu ft =0.28m3 1st = 0.9 t7 1 acre = 0.40 ha or m2 In several cases the royalty is a percentage of the finished products, sale price and is levied against either the amount produced or the amount sold. We thank those who contributed information for the table: J. Dunn, T. Eyde, K. Loda, L. Morgan, F. Nix, H. Sorenson, and L. Williams. Several people have said they would like this to be an annual tabulation. That can happen if new information comes to the writer. What appears in the table is only a very small fraction of the cost information relative to the various commodities and the geographic areas for which there is royalty information. If you find this column of interest and possess information write or call: H. L. Bourne, c/o Neyer, Tiseo & Hindo, Ltd., 38955 Hills Tech Dr., Farmington Hills, MI 48018, (313) 553-6300. Only with new information can this become an annual and current source of reserves costs.

Jan 8, 1986

By H. Lyn Bourne

This is the fifth annual tabulation of mineral royalty information. This tabulation, like the previous editions, includes all of the earlier data. There are also 60 new entries. In addition to royalty information, some entries show the cost of purchased reserves. Two articles relative to the evaluation of minerals reserves appeared in December, 1986. R.H. Paschall (In the Aggregate, ME, p 1139) wrote a good article, although it lacked specific royalty data. However, this author takes exception to two ideas in Paschall's column. Paschall contends that the royalty rate does not affect the mineral appraisal. This present author could not disagree more. Paschall also claims the location of an industrial mineral deposit is the only serious or practical caveat in comparing royalties. Comments received here from readers helped make the list of caveats that are cited each year. The readers will decide which factors influence the mineral value for their commodities of interest. Paschall's point about the relationship of the parties who are negotiating a royalty agreement is important and very well taken. The other article, written by William Vernon (Pit and Quarry, December 1986), gives a step-by-step process on how to conduct a mineral appraisal. The article cites three reasons for an appraisal: transfer rights; collateral for a loan; and taxation. A fourth reason is to establish adequate compensation for reserves lost through condemnation. This author has appeared in several court cases where compensation for loss of mineral reserves through condemnation required a mineral appraisal. Royalty rate becomes an important factor in the appraisal process, although the Pit and Quarry article refers to that part of the valuation equation as "profitability." Both articles were well written and are recommended reading for those interested in mineral valuations. The same caveats that have appeared in previous columns relative to factors that influence the value of reserves are restated. The data in the table serve as a general reference and are not intended to present an absolute scale of reserves costs. Several factors influence the value of any mineral commodity. The factors include: • location/transportation - especially significant for most industrial minerals; • market conditions both for the commodity and the company acquiring the right to mine; • quality or grade of the deposit as it reflects the amount of processing/beneficiation necessary to produce the finished product; and • legislative restrictions and conditions for mining a given material at a given site. These and other factors will significantly influence the cost of reserves. The table shows the range of royalties and the variations in the basis of computing the fees. In a few instances, it gives the cost of acquired reserves based on purchase price and quantitative estimates of the material in place. The table lists the commodity in column 1, and the subsequent columns give: • the location by state, US geographic area, or Canadian province ; • the cost - R for royalty and P for purchased cost; • the year in which the lease or purchase agreement occurred; and • comments or footnotes for more information. The cost column requires more explanation. The units may refer to cubic yards (/cu yd), cubic feet (/cu ft), short tons (/T), or acres (/A). 1 cu yd = 0.76 M2 1cuft = 0.28m3 1 st = 0.9072 t 1 acre - 0.4047 ha or m2

Jan 7, 1987

By H. Lyn Bourne

This is the seventh annual tabulation of royalty information. It is also the first year in which some data have been deleted to make room for new data. The concept of royalties evolved from a time when the government owned all of the land, including mines, to the situation where free miners won the right to claim minerals but paid a portion of their production to the royal treasury. Today, a mineral royalty is a payment to the owner of the mineral rights for the privilege of producing the mineral commodity. However, some people incorrectly believe that the selling price and the royalty are the same thing. The contract between the owner (lessor) and the mining company (lessee) is the mineral lease. Some clauses that are common to mineral leases include: identification of property, granting clause, reservations, definitions, royalty rate, taxes and title, indemnity, termination, inspection, assignability, successors, and reclamation. There often are variations in royalty rates for a given commodity that reflect differences in location, quality, market conditions or public versus private ownership. History In the time of ancient Rome, the government owned the mining properties by virtue of conquest. It would lease the mines to favored citizens who would pay rent to the State. Various conditions of sovereign ownership of both land and mineral rights continued in Europe until the Renaissance. As the laws evolved for land ownership by private citizens, the concept that minerals belonged to the State (King, Crown, sovereign) continued until about the 15th century. Free miners challenged the notion of sovereign ownership and won the right to discover and claim minerals. But a portion of their production had to be paid to the sovereign - a royalty. So, the original concept of a mineral royalty was a tax on production that was due to the Crown or Church. The term mineral royalty, as it is known today, is a payment to the owner of the mineral rights (formerly the royal owner) for the privilege of mining and producing the mineral commodity. The owner of the mineral rights, the lessor, and the mine operator, the lessee, enter into an agreement to mine the property. The agreement is the lease. While this concept is common, there are some who do not understand that the royalty is a portion of production paid to the owner as agreed on in the lease document. This author has seen reports where the selling price of a commodity has been quoted as the royalty. ("They get 70 cents a ton royalty at their pit and the guy down the road only has a 65 cent royalty.") These reports have been authored by people not familiar with the mining industry. Lease clauses In addition to the amount to be paid the lessor, there are several other items to be addressed in the lease agreement. The following list may not be all inclusive, but briefly describes most of the common clauses any good mining lease should contain. Identification: This opening clause names the owner (lessor) and the operator (lessee), the address of each, and gives the legal description of the property. Granting clause: This part of the lease gives the time period or duration of the agreement and information about renewal periods. It also has language about the exclusive right of the lessee to mine the property. Reservations: If the owner wants to exclude any portion of the property or set some specific conditions about the operation, there needs to be a clause that describes these reservations. Definitions: This section should address some of the technical terms that the lessor may find confusing - short tons versus cubic yards, dollars versus percentage of average selling price, any escalator indices such as consumer price index or producer price index, and material mined versus material sold. Royalty: This section spells out what the royalty rate will be, how often it will be paid, if there is an annual minimum, the pay dates, and how the records will be kept. This section also describes the conditions under which the lessee is exempt from the annual minimum - natural disasters, strikes, governmental actions, or other causes referred to as force majeure. Taxes and title: The lease needs to identify who is responsible for the property taxes, severance taxes (if applicable), and other taxes that relate to the mining activity - taxes on equipment, improvements, or stockpiles. This is a good place in the lease for the owner to certify his ownership of the property and its mineral rights and also certify that no other leases are in effect. The lessees may want language that allows them to pay mortgages or other debts on the property to keep their lease in effect. Indemnity: This portion of the lease identifies that the lessee assumes the risks for lessee's mining operation. Lessor should expect indemnification by the lessee through standard insur¬ance policies - workers compensation, liability and property damage. Termination: Both the lessor and lessee want language that will allow them to terminate the lease. This section of the lease describes the conditions under which one of the parties may terminate the lease (failure of the

Jan 1, 1989

By H. Lyn Bourne

This is the ninth annual tabulation of royalty information. Again this year, some of the older information has been deleted to make room for more than 30 new entries. Several articles and publications crossed the author's desk this past year that relate to mineral valuation and mineral royalty. Tom Loucks presented a paper, "The Valuation of Hard Rock Mineral Property," at the Rocky Mountain Mineral Law Foundation in Santa Fe, NM in July, 1990. His paper gives an indepth explanation of the definitions and concepts related to mineral valuation. It includes descriptions of numerous legal cases that have dealt with mineral valuation and proper reference is given for each case. Loucks works for the Denver Mining Finance Co. Gold royalties generally range from 5% to 7%, net smelter return. However, Severn Brown sent information that shows a much wider variation. Echo Bay Mines reported in its 1989 annual report royalties that range from 1.5 % to 30% for gold from various gold properties. Brown also sent a copy of an article that appeared in the Dec. 27, 1982, issue of Fortune magazine. This issue carried an article by Walter Guzzardi, Jr. "The Huge Find in Roy Ash's Backyard." The article gives the history of Newmont's leasing in Nevada on property that became the Carlin, Bootstrap and Blue Star Mines. The article states that the initial royalty was 10% that escalated to more than 16%. Another property, the site of Gold Quarry, provides an 18% royalty to the same own¬ers. The article makes interesting reading for those interested in mining history.

Jan 1, 1991

By H. Lyn Bourne

This is the eighth annual tabulation of royalty information. Again this year, some of the older information has been deleted to make room for nearly 30 new entries. Several articles and publications have appeared recently that relate to mineral royalty or mineral valuation. R. B. Parsons wrote "Mining agreements, royalties and profits" (CIM Bulletin, November 1988). He distinguished between net smelter return (NSR) and net profit interest (NPI). Parsons used examples to show the difference between these royalty payment methods. Mining Engineering (January 1990) carried an article by H. V. S. Tingley entitled "Using business due diligence to help evaluate mineral deposits." The article identifies some factors that must be examined during mergers or acquisitions in the mining industry. Since each mining operation is unique, each has risks and opportunities that need recognition and evaluation. The author suggests that a team is necessary for a proper evaluation because no one person has expertise in all of the factors that must be examined. Also in January's Mining Engineering was "Limestone mining: Reserves and valuation," by B. C. Lewis and R. P. Moran. They presented two case studies of valuation of limestone reserves. One was a 109-hm2 (270-acre) parcel in West Virginia and the other a 121-hm2 (300-acre) tract in Alabama. The authors discussed risk, discount rates, and royalty methods as financial parameters in valuation of limestone reserves. Two papers were presented at the SME meeting in Las Vegas, NV in 1989 that bear mention. J.G. Russell's talk was entitled "Valuation of industrial

Jan 1, 1990

By H. Lyn Bourne

This is the 10th annual tabulation of US mineral royalties published in MINING ENGINEERING. The first year, 1982, the author solicited information about royalties and the cost of reserves. That column contained only a few royalties - not enough to tabulate. Since then, the response has been sporadic but the entries have grown to more than 300. Some have been deleted. Some of the older information has been deleted to make room for new entries. All indications suggest that the readers enjoy and use the information. But more information is needed. Russian practice In 1989, this column gave a brief history of mineral leasing and royalty payments as the concept applies to mining in the United States. This year's narrative deals with information about the mineral ownership in Russia. That country is in political and economic turmoil, including administrative systems and methods. And many laws are likely to change. What follows describes the Russian system of mineral ownership as of early 1992, according to Kirill Kavun. He begins "All the subsurface space of the Russian Federation with minerals contained belongs exclusively to the state. This forms the Common State Mineral Fund. Land parcels may be state, municipal, public or private property. They may be let to be owned and used by individuals, juridical persons, national/territorial or administrative/ territorial formations." This seems to apply to surface rights, as known in the US.

Jan 1, 1992

By H. Lyn Bourne

This is the 12th year for this column and the 11th in which the royalty data have been tabulated. This year adds 20 to 30 new entries. There are, however, some deficiencies that the readership hopefully will fill. The most common mineral commodity is construction aggregates - either sand and gravel or crushed stone. There are several states where no royalty information was available for either commodity. Readers can help share information about these missing states, so next year there will be fewer states without information. Severn Brown again sent helpful information from the Prospectors and Developers Association of Canada (PDAC). The summer 1992 issue of PDAC Digest recommended"... the most useful technical paper ever published for economic geologists...." "Net smelter return models and their use in the exploration, evaluation and exploitation of polymetallic deposits" was written by R. Goldie and P. Tredger (Geoscience Canada, Vol. 18, No. 4, pp. 159-171). Last year's column described leasing practices in Russia. Some new information has been gathered since then. Kirill Kavun is the managing director of the International Geoeconomic Center in Moscow. He sent two publications from 1992-"Regulation on the procedure of licensing the use of the subsurface," and "Law of the Russian federation on the subsurface." Both are supplements to the magazine Mineral Re¬sources of Russia, Economics and Management.

Jan 1, 1993

By H. Lyn Bourne

This marks the 15th consecutive year for this column. During 1995, readers were asked to supply royalty data for construction raw materials especially for states where none is available. The response was discouraging and royalty data are still missing for several states for either sand and gravel or crushed stone. Several readers have said that this article has merit but more new information is needed to justify its continuation. Several articles and pieces of news relative to mineral royalties appeared in the trade journals. R. Lee Aston (E&MJ, November, 1995, p. 16N) described South Australian royalties as amended by the government in1994. The royalty rate (a percentage) was lowered but the assessed value for minerals was raised and the current rate amounts to 20 cents//t (18 cents/st).

Jan 1, 1996