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By J. B. Offei, K. Awuah-Offei

Mining companies registered with the SEC were required to comply with Regulation S-K 1300 for their annual report covering the first fiscal year ending on or after January 1, 2021. Consequently, most mining registrants filed their first S-K 1300 compliant disclosures in 2022. The US Securities & Exchange Commission (SEC), as part of its disclosure review program, has been issuing comment letters in response to these filings. This paper presents an overview of the trends in these comment letters. The authors reviewed comment letters retrieved from the SEC’s EDGAR database based on Standard Industrial Classification (SIC) Codes that cover mining, the content of the comment letter (whether it references S-K 1300 or not), the names of SEC staff listed in the comment letters, and other criteria. The analysis shows the SEC staff's reviews have been comprehensive covering the breadth of S-K 1300 and eliciting compliance with the rule. The staff through their comments are eliciting all the disclosures required by S-K 1300 and are not allowing registrants to substitute disclosures based on other standards for S-K 1300 disclosures. It is important, however, not to over generalize as the comments are based on the particular context.

Feb 1, 2023

By E. J. Wade

My subject is gold price forecasting and monitoring as an important aspect of gold marketing. While I 'm specifically addressing gold, it is understandable that many other commodities could be readily substituted. Gold marketing must be studied as three distinct processes, and it is my intention to cover each of these processes in turn. First I?ll cover the process of gold price monitoring and forecasting in some detail. In order to select a method, or combination of methods, to be used to sell gold a determination of the future price profile is essential. The profitability of the sales effort will be determined, to a large extent, by how accurately the future price behavior of the gold market has been forecast.

Jan 1, 1985

By D. L. Moellenberg

Under various state laws enacted mostly within the last 20 years, reclamation requirements and standards for hard-rock mining operations have been established virtually everywhere in the western United States. Unlike the uniform and detailed coal mine reclamation requirements under the federal Surface Mining Control and Reclamation Act ( "SMCRA" ) and state programs mode led after SMCRA, the various state law hard-rock mine reclamation requirements are based upon a variety of objectives, and therefore are subject to varying standards from state to state. While the diversity of reclamation requirements complicates the determination of what reclamation measures will be required at any particular mine, there are valid reasons for this diversity. There are dozens of different commodities mined in the United States, and mining methods are different for each commodity. Local natural conditions such as climate, precipitation, geology, hydrology, and biology vary widely across the county. Site-specific conditions also affect mining and reclamation methods. Also, factors such as economics, land use, and environmental protection issues receive different priorities in different states and communities within those states. State reclamation requirements in general provide the flexibility to consider site-specific circumstances, allowing operators to design and engineer the best reclamation measures for each mining site. To the mine developer or manager, reclamation requirements must be translated into design, operational, and closure measures for mine planning. Each of these measures must then be assigned additional costs to be factored into the economic decisions for a particular mining operation. On a broader level, reclamation costs must be factored into decisions such as where to invest in exploration and mine development. The purpose of this paper is to provide a summary of the state non-coal mine reclamation requirements in twelve western states. This summary comparison may be useful as a starting point in considering how local reclamation requirements will impact potential mining costs.

Jan 1, 1994

By P. Zhang

A 1989 FIPR characterization study of the future phosphate resources in Florida showed that MgO would be a problem with both the pebble and concentrate as phosphate mining moves deeper. Since the ratio of concentrate to pebble will become higher and higher in the future, reducing Mg content in the concentrate by a small margin would allow blending of a large portion of the high-dolomite pebble. This research was conducted based on that logic. The following six approaches were tested for reducing MgO content in the flotation concentrate: (1) Adding a dolomite depressant in the rougher flotation step; (2) Dolomite flotation on the rougher concentrate with and without grinding; (3) Dolomite flotation on the cleaner concentrate with and without grinding; (4) Scrubbing the flotation feed; (5) Scrubbing the rougher concentrate; (6) Scrubbing the cleaner concentrate. Successful methods include adding a dolomite depressant in the rougher flotation, dolomite flotation on the cleaner concentrate with grinding, and scrubbing the cleaner concentrate in quartz sand. These techniques could reduce MgO content in the final concentrate by 20-40%. The flotation process could achieve a concentrate with the lowest MgO content, but it is the most expensive approach. Adding a dolomite is inexpensive and easy, but the effect is limited. Overall, scrubbing may be the most promising technology for this purpose.

Feb 23, 2014

By Hongling Wang, DI WU, Shuai Li, Hui Shu

Isothermal reduction experiments on carbon-bearing pellets of copper slag were investigated by the thermogravimetric method with biomass carbon as a reducing agent. The results indicated that the reduction process of copper slag‑biomass composite pellets was dominated by gas phase diffusion, and the apparent activation energy was 88.44 kJ/mol. In the temperature range from 1000 to 1200 °C, the metallization rate of pellets increased with increasing temperature, and the maximum metallization rate was 78.4%. The optimal reduction temperature of CSBCP (copper slag-biomass composite pellets) was 1200 °C.

Nov 23, 2022

By J. D. Forrester

In striving to develop this discussion about "Manpower for Industrial Mineral Industries" two fundamental classes of manpower are encountered. These are: 1) The Labor Force, comprised of unskilled and semi-skilled, nonprofessional personnel who participate in conducting economic, mineral deposit operations and; 2) The Professional People involved in the science, engineering, and management of such industrial enterprises. The commentary given here will be directed primarily to a review of the characteristics of the second or latter class. To pursue successfully a career as a scientist or engineer in today's industrial and social complex, it is necessary that technical knowledge must have been acquired by training and study in an institution of higher learning. Also, to act effectively, the individual must have achieved some degree of specialzation, although this element often is developed to most notable degree by post-graduate exposure and experience. In addition, and especially in the case of "management," it is desirable, indeed it is even necessary, that an individual recognize and appreciate the fundamental humanistic-sociological controls, and their nuances, as these elements exist to shape his total environment.

Jan 1, 1969

By Margreth Tadie, Chalwe Chibwe

Physicochemical properties of copper electrolytes are a strong fundamental consideration in electrodeposition processes during electro-purification and recovery of copper. Their influence extends to mass transfer as well as energy consumption during the electrodeposition process. In this study, the influence of electrolyte composition on electrolyte physicochemical properties was investigated to review the existing literature data. This review of data is considered necessary as more and more electrowinning models are being developed for process prediction and optimisation and a need of such data is required for accurate prediction of physicochemical properties. The major components of importance to the formation of smooth high-quality and high-purity copper cathodes at optimum current efficiency are considered the species in solution. These include Cu ions, Fe ions (major impurity), H2SO4, and a smoothing agent additive. A 5-factor, 2- and 3-level experimental design was employed to determine the effect of copper (35 and 45 g/l), sulphuric acid (160 and 180 g/l), iron (1, 3, and 6 g/l), polyacrylamide additive (2, 5, and 10 mg/ l), and temperature (45 and 55 °C) on electrolyte density, conductivity, and the diffusion coefficient in synthetic copper electrowinning electrolytes. The major species in a copper electrowinning electrolyte are found to be the most relevant for prediction of physicochemical properties. These results indicate that relatively simple empirical models are sufficient for modelling of the electrolyte domain in electrowinning, without the need for the generation of vast amounts of complex experimental data.

Feb 1, 2021

By Thomas B. Dellinger

Since 1950, rotary-drilled, large-diameter holes, "big holes", with depths to over 300 feet and diameters of over 30 inches have become numerous and widespread. Fifty such holes have been drilled for access shafts to LPG mined caverns, Over 70 holes have been drilled for various other commercial activities. Over 150 holes have been drilled by the AEC for atomic testing purposes. These holes have ranged up to 300-inch diameters with 1600-foot depths, 120-inch diameters with 570-foot depths, and 72-inch diameters with 4800-foot depths. Equipment is now available to drill a wide range of ?big holes? for varied requirements. At least a dozen drilling contractors are participating or have participated in the drilling of "big holes". The accompanying tables show pertinent historical, technical and economic data on over 250 holes. The illustrations to be presented concurrently with this paper show the various equipment and accessories now in use. (See Appendix I for captions of illustrations.)

Jan 1, 1966

By W. C. Meyer

A physical model of flotation, derived from viewing froth as a kinetic species since it constitutes the carrier of ore particles, not only agrees with and is simulated by engineering math models, but is statistically verified by actual laboratory flotation data. The model couples the mechanical removal of froth using paddles with the more rapid chemical interactions taking place in the bath. It clearly shows that the kinetics of mass removal is dictated by flotation cell dimensions, paddle speed, and, more importantly, froth characteristics. Some conclusions and predictions of the model are presented.

Jan 1, 1982

By R. S. Shepard

The closing remarks of a paper which I presented at the annual AIME meeting at Dallas, Texas during February of 1963; contained a forecast of increased activity in trackless underground ore mining which finalized that presentation. At that time, HAD I been peering through my brightest rose colored glasses, I could not have foreseen the unprecedented rapidity of acceleration of underground ore mining methods which has since ensued. From Death Valley, California diagonally to St. Johns, New Foundland; from Australia to Africa to Sweden to France and Germany; from South America to Southern Mexico to Northern Saskatchewan and Northern Manitoba the expansion of trackless underground ore mining methods has probably progressed at a faster rate than any other revolutionary' change in the history of underground ore mining.

Jan 1, 1967

By F. L. Wilke

Underground mining is a very complicated and complex industrial activity. The uncertain and, in most cases, the incomplete knowledge of the geological and mineralogical nature of the deposits can cause unforeseen difficulties. For a safe and uninterrupted operation, in addition to good planning and scheduling, reliable and up-to-date monitoring and control of all processes and conditions become necessary. Today, this is even more important in view of increasingly difficult working conditions, poorer grades, and more complex and expensive machinery. In short, large capital investment and higher risk of financial losses are involved in modern-day mining operations. Monitoring and control of the underground mining process has become a very complex and difficult task in itself. Many different systems are available, and the correct choice .is of utmost importance from both the economic and safety points of view. This chapter will deal with aspects of underground production monitoring and control. There are, however, many other areas of equal importance which are covered in an excellent manner in a hand- book by Olaf (1976) on monitoring and control of underground operations.

Jan 1, 1979

By K. M. Stone, N. J. G. Masson, A. C. Woollett

The Jabali zinc deposit in Yemen contains at least 9.4 Mt (10.4 million st) of ore at a grade of 10.7% zinc, 2.2% lead and 77 g/t (2.2 opst) silver. The zinc occurs as smithsonite with minor hydrozincite. The Jabali ore does not produce a zinc concentrate of sufficient grade to be acceptable to a conventional zinc smelter, and it has been necessary to formulate a less-conventional development plan. This involves the construction of a mine and concentrator at Jabali and a metal production facility using a new flowsheet designed specifically for the treatment of oxide material at Yanbu, Saudi Arabia. To give the facility the necessary economies of scale, the Jabali concentrate will be supplemented by feed from other deposits, this may be either oxide or sulfide material. The paper outlines the geology and proposed mining and treatment operations at Jabali, presents the flowsheet for Yanbu and estimates preliminary costs for both operations.

Jan 1, 2003

By Paavo Eerola

In May of 1984, it was decided that Outokumpu Oy would design and build a new nickel flotation mill to process ore from the newly discovered Enonkoski mine in eastern Finland. Since there hart peen a number of successful process charges in the existing mills, the design effort included the study and incorporation of several new developments, including all-autogenous grinding, "flash flotation", lane cell roughing, large cell cleaning and a computer-based, profit optimizing, process control system. The paper discusses the background and results of those studies, and a description of the resulting mill which will begin production in 1986.

Jan 1, 1985

By William C. Peters

The frustration encountered by exploration crews in connection with land acquisition could be graphed to show a correlation with the natural law that everything tends to become more so. Figure I shows a rather common, situation. The combinations of ingredients are almost limitless and the resulting brew is often poisonous to an exploration man. A single step, that of taking a series of deep soil samples is often delayed until some sense can be made from "floating" unpatented claims which are obscure in orientation as well as position, placer claims overlapping lode claims, location posts with empty Prince Albert cans, and claims with no apparent assessment work for ten years. Add to this some patented claims with¬out monuments, a state or federal withdrawal area which may or may not invalidate pre-existing claims, a loosely defined tunnel site, and some ranchers who understandably resent the separation of surface rights from mineral rights. The picture is familiar to exploration men. One approach to such problems is to ignore them until someone voices an objection -- but then an even more chaotic situation is likely to develop. Another practice is to stake new claims to cover all ground that is "open" at first glance and then find out if there are conflicts so that the new claims can be adjusted accordingly.

Jan 1, 1970

By Brian F. Taylor

The Mexican fluorspar industry is faced with and will face serious problems, some of their own making and others beyond their control. However, they still offer the most secure source of fluorspar for North American' consumers. Since 1975, even in light of declining markets, they have, increased then production capabilities' as shown in Table #1. In analyzing Table #1, we note that Compania Miners Rio Colorado has closed down due to their ore reserves being exhausted. Fluorita de Rio Verde expanded their acid grade fluorspar capacity in anticipation of additional North American business. Campania Miners Las Cuevas presumably increased capacity to meet their North American contractual commitments and to supply their own hydrofluoric acid plant (Fluorex) at Juarez, Mexico. Historically, the Mexican fluorspar industry has relied on the United States as the mainstay for their sales. As shown in Tables #2 and #3, the Mexican share of the United States market has moderately decreased. However, as noted in Table #4 the volume loss is substantial as explained below.

Jan 1, 1985

By B. Pina

The conversion of maf coal to pyridine solubles and gas was investigated in a microautoclave batch reactor for two Kentucky washed coal samples (Ky. #9 and Ky. #11). Solvent hydrogen donor strength was controlled by the tetralin content of a mixed 1-methyl naphthalene-tetralin solvent. Primary liquefaction conversions greater than 90% in 10 minutes of reaction time at 427°C were achieved in liquefaction solvents with moderate hydrogen-donor strength (circa 40% tetralin). A modified irreversible first order rate expression, containing a parameter (a) to account for the intrinsic reactives of the maf coal, described the experimental kinetic data rather well. The integrated form of this rate expression is -k1e x = a (a- ß)e (eq. 1) Parameter ß in equation (I) is the pyridine solubility of the starting maf feed coal, x is the primary liquefaction fractional number of conversion, k1 is the specific reaction velocity constant and ? is reaction time. Primary liquefaction rate was found to be quite temperature sensitive and independent of coal when a liquefaction solvent containing 40% or more tetralin was employed. Primary liquefaction rate appears to depend on liquefaction solvent hydrogen donor strength for solvents containing = 40 wt.% tetralin. The intrinsic reactives in the maf feed coal or a appear to depend mainly on the inertinite group maceral content of the coal for the two coals studied in liquefaction solvents containing 3 40wt.% tetralin. In contrast, a appears to decrease in liquefaction solvents of low donor strength., i.e; solvents with less than 40wt.% tetralin.

Jan 1, 1984

By H. Rush Spedden

A process has been developed and piloted to reject copper, lead, iron, phosphorus, bismuth, antimony, elemental sulfur, and insol from molybdenite concentrate without decomposing the contained molybdenite and rhenium. The impure concentrate is first heated with concentrated sulfuric acid at 260 to 290°C for 1 hour. This bake not only oxidizes the contaminating sulfides, but also activates the concentrate for later rejection of insol by flotation. Two stages of leaching follow the sulfation step. The first is an acidified water leach which extracts the oxidized copper, iron, and phosphorous; the second leach rejects the lead, bismuth, and antimony into a warm concentrated solution of sodium chloride. Final upgrading is achieved by conventional froth flotation. The chemistry of the process as well as results obtained from its implementation in a 5,000 lb/day pilot plant are presented.

Jan 1, 1971

By S. M. Woodring

Research objectives included 1) determine relationships if any between spectral response of soil and soil textural groups, Unified Soil Classification subgroups and selected landforms and 2) develop computer assisted techniques for engineering soils mapping of remotely sensed data. The sire in northeastern Kansas, 1.6 Km by 43 Km (1.0 mi by 27 mi), contained glacial and alluvial soils. Multispectral scanner data (0.40 to 1.80 pm) collected at 915 meters altitude (3,000 feet) were analyzed using two distinct computer techniques: the nonsupervised approach involving delineation of soil training areas directly by computer and the supervised approach entailing training area selection manually by the researcher. Computer classification of surface materials follows both methods. Non supervised analysis results failed to show a consistant relation- ship between landform type and soil spectral class. Landforms correlating well displayed either unusually bright or unusually dark spectral signatures. Supervised analysis results showed a strong relationship between soil texture and soil spectral class. A moderately strong tie was shown between engineering soils groups (ML, CL, CH and OH) and their respective spectral classes, and a weak association between landform type and soil spectral class. An analysis procedure for engineering soils mapping by computer of remotely sensed data was developed. 1. Locate cultural features by visual examination of imagery. 2. Produce generalized bare soil-vegetation- water map using nonsupervised technique. 3. Outline significant soil fields for computer training using supervised approach. 4. Computer-classify entire area based on these soil fields.

Jan 1, 1974

By X. Baolin, R. Guru, M. Peiravi, M. K. Mohanty, Z. Qian, R. Ma, Z. Yude, L. A. Ackah

"Acid mine drainage (AMD) is produced when exposed pyrite (FeS2) reacts with air and water to form an acidic solution that usually contain contaminant levels of heavy metal ions. AMD can potentially contaminate surface water and soil if not treated. The primary objective of this study was to investigate the removal of dissolved aluminum, iron and zinc metal ions from natural AMD using water treatment residue (WTR), a low-cost adsorbent. WTR sorbent generated as waste material in drinking water treatment plants (WTP) was characterized and utilized for the sorption of Al, Fe and Zn in AMD collected from an abandoned coal mine site in southern Illinois that generates approximately 20 gallons per minute of AMD. Sorption experiments were performed using batch technique to obtain rate and equilibrium data. The effects of various parameters on sorption capacities of WTR were observed by varying contact time, pH of the AMD and WTR dosage. The adsorption studies showed rapid uptake in general for the first 80 minutes for Fe and Zn but much earlier for Zn. Further increase in contact time did not show significant change in equilibrium concentration indicating the onset of adsorption equilibrium. After the batch treatment of the AMD water with the WTR, the removal of Al, Fe and Zn were 99.8%, 99.85% and 95.5% respectively. The pH of AMD increased from 2.64 to a near neutral point of 6.74 after treatment. The laboratory results show that the low-cost WTR, which is an abundantly available industrial waste, has proven potential to significantly reduce the high metal ions in acid mine drainage. INTRODUCTION Mining activities provide the basic raw materials needed for infrastructure development and economic growth world-wide. However, it is well recognized that mining activities have been the cause of a variety of environmental pollutions, including AMD. Water seeping out of an old abandoned mine is generally characterized by low-pH with heavy loads of dissolved sulfates (SO4) and metal species such as Fe, Al and Zn among other dissolved elements categorized as toxic metals. The Bureau of Land Management’s Abandoned Mine Lands (AML) program reported the existence of about 46,000 abandoned mines in the United States. Several environmental problems have been reported to be associated with these mined out sites such as heavy metal poisoning, loss of vegetation, air pollution etc. (Boulanger & Gorman, 2004)."

Jan 1, 2017

By J. R. Cobble

The Bureau of Mines has developed a process to improve the leaching kinetics of diffusion controlled systems. The system features the Bureau-developed turbomill, an attrition grinder which scrubs the reaction product coating away from the unreacted mineral grains during leaching. The system can be continuously operated at any temperature up to the boiling point of the leaching agent. This paper describes the research on the dissolution of chalcopyrite with acidified ferric sulfate which forms a sulfur product on the unreacted chalcopyrite surface. This method is a hydrometallurgical alternative to chalcopyrite smelter technology which eliminates S)2 emission problems with its associated costs. Batch testing at 90? C with the chalcopyrite/ferric sulfate system resulted in better than 99-pct extraction of copper. At an optimal energy consumption of 1,520 kW h/st, 95 pct of the copper was extracted. Recent work has been directed to development of a continuous system and SX/EW treatment of the resulting pregnant liquor from the chalcopyrite/ferric sulfate leach.

Jan 1, 1991