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By Carl Lubbe, Ron Frye

Numerous articles have been written regarding the effects of blast control plugs in an attempt to quantify stemming ejection rates, air overpressures, fragmentation’and other parameters measured using these devices. In an effort to further attempt to understand the function of these devices, field and laboratory research conducted with various stemming devices was performed to enhance existing data sets and analyze otherphenomena that occur when these products are used.

Jan 1, 1998

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016

By Robert C. Rabeler

Soil and Materials Engineers, Inc. (SME) has utilized drilled cast-in-place (D-CIP) piles on a number of projects in the midwest. These foundation systems have typically consisted of drilling an 8 to 9-inch diameter borehole with a rotary type drill rig or driving a casing with a small hammer. A structural steel member is installed in the center of the excavated space, and the borehole or casing is grouted to complete the installation of the D-CIP pile. This type of piling system has also been called: mini-pile, micro-pile, or drilled-in pier. The capacity of these piles varies depending upon subsurface conditions, as well as the structural capacity of the pile. The structural capacity can be modified based on the size and yield strength of the structural steel member. SME has used the D-CIP piles for underpinning of lightly-loaded structures for a number of years. Steel brackets can be welded to the structural steel member in the center of these piles, and the bracket extended underneath existing foundations to provide proper foundation support. D-CIP piles have also been used for new construction where access was limited. Recently, SME had the opportunity of providing design as well as construction monitoring services for a unique project where these piles were used, but at much higher capacity. The project involved adding seven additional floors on top of a five-story building (total of 12 stories). New columns were extended through the existing building to support the new floors. Access to construct foundations was available to one level of underground parking beneath the structure, as well as to a basement area. Access required equipment to travel through a 3-foot wide hallway. A special duplex drilling machine was used to access the foundation locations and to install the piles in a limited headroom condition. Eight-inch diameter D-CIP piles were extended to a depth of approximately 40 to 50 feet below grade and socketed into a dense clay till or sandstone, and No. 18 or No. 20 threaded bars were installed in the center of these piles. The design pile capacity was as high as 190 kips and were verified by a compression load test. The load test was performed with limited access and headroom. These piles were installed by Spencer White and Prentis Foundation Corporation (SWP). For conditions where rock or hard soils are encountered at reasonable depths, D-CIP piles can provide working load capacities comparable to larger driven steel piles. The ability of the equipment to access very restricted areas, combined with the high capacities results in a very attractive solution to a number of difficult foundation problems.

Jan 1, 1999

By S. E. Khalafalla

In support of its goal to maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines has investigated a novel hydrometallurgical system with sulfur dioxide. Differential leaching with dissolved SO2 of manganese, nickel, and cobalt from their hydrous oxides was found to be very rapid and efficient--almost instantaneous and quantitative. In this method a given weight of mixed oxides previously ground to minus 200-mesh is slurried with a leach solution containing a specified quantity of dissolved SO2 for 10 minutes at room temperature and ambient pressure. An empirical leaching parameter, R, is defined as the ratio of the number of SO2 moles in the leaching solution to the weight of the metal oxide charge. Plots of the variation of metal extraction with the ratio R generate a series of sigmoidal-shaped curves, each of which is characteristic of a specific metal extraction. A threshold value of R is required to initiate the leaching of a given metal from the mixed oxides. Once this threshold is reached, the metal recovery can increase to more than 95 pct in very short times. For increasing values of R, the extractability of various metals by SO2 follows the order: Mn > Ni > Co >> Fe, Al, Cu. Differences in the threshold R values permit a variety of metal separations to be made simply by adjusting the quantity of SO2 in the contacting solution. Success in this leaching system depends upon comminuting the sea nodules to less than 0.149 mm (100-mesh). Above this critical size, leaching is slowed due to the inaccessibility of inner particle reacting groups to the SO2 leaching agent. This results in nonselective extraction and less extraction of preferred metal values. At or below 0.149 mm, leaching by SO, is possible with all its attributes of selectivity, sensitivity, and rapidity. Leaching with HC1 solutions of the same pH level as dissolved SO2 yielded mixed, slow, and incomplete metal extractions. This observation rules out any interpretation based on hydrogen ion as the leaching agent. The leaching curves resemble the complexometric titration curves of heavy metals with specific coordination species.

Jan 1, 1981

By P. Rosten

US mine production of iron ore in 1984 showed some improvements compared to 1983. But reduced demand from the iron and steel industry caused temporary shutdowns of many iron ore mines and pelletizing plants. US raw steel production in 1984 was slightly above 1983, but still at a depressed level. Production was 83 Mt (92 million st), compared with 77 Mt (85 million st) in 1983 and 68 Mt (75 million st) in 1982. Two major production trends continued in 1984. They were the increased production from electric furnaces and the growing use of continuous casters. Electric furnace production included 33.2% of the steel poured in 1984, compared with 31.5% in 1983. Continuous casting was used for 39% of 1984 steel production, compared with 32.1% in 1983. Statistical Process Control Statistical Process Control (SPC) has taken on new proportions in the iron ore and steelmaking industries within the last year. This mathematical technique is used to monitor, control, evaluate, and analyze a manufacturing process. The technique charts variability of important quality parameters. Training and adaptation of SPC techniaues for process control have been initiated at Inland, Steel's Minorca, Pickands-Mather's Hibtac, Cleveland-Cliff's Empire and Sherman operations, and at Reserve Mining. One of these operations has requested its bentonite supplier provide SPC charts on quality specifications. Some of the steelmaking operations (Inland Steel, Bethlehem Steel, Dofasco, LTV Steel, National Steel, Stelco, Weirton Steel, and Wheeling-Pittsburgh) have set up SPC programs within their operations. And they also have insisted that some of their suppliers use SPC. Plant Shutdowns The permanent closure of Stelco's Griffith mine at Red Lake, Ontario, has been delayed by one year. This gives employees more time to adjust. The mine is now set to close in April 1986, instead of April 1985. Sidbec (Canadian government) and its other partners (including British Steel Corp., Quebec Cartier Mining, and US Steel) closed its iron mining operations at Gagnon, Quebec. The pellet plant has been leased to Quebec Cartier. New Iron Ore Operations The massive Carajas iron ore project in Brazil is scheduled to come onstream in Jan. 1986. It is to achieve full-scale commercial shipments by July of that year. The 66% iron crude ore requires only crushing and screening before shipment. The product consists of 83% sinter feed and 17% coarse ore. Annual production capacity will be 32 Mt (35 million st) when the project is completed. Principal customer for the ore is Nippon Carajas Iron Ore Co., a consortium of Japanese steel mills. The Arab Iron & Steel Co. (AISCO) has started up a $US300 million, 3.6 Mt/a (4 million stpy) iron ore pelletizing plant built by Kobe Steel Ltd., at Al Hidd-hide in Bahrain. By 1986, this grate-kiln-cooler plant will supply high quality iron ore pellets to feed direct reduction plants in the immediate Gulf area and Far East markets. Iron ore supplied from Brazil, Peru, India, and Mauritania provides the feed to the pellet plant. Hydrated lime (2%) is used as a burden.

Jan 5, 1985

By L. Gilbert

Recent changes to environmental legislation and trends in the environmental regulation of mining in the Northern Territory are being driven by (among other factors) Federal Government policies and international agreements on the environment. These trends are discussed and the expected application of the NT Water Quality Management Strategy (based on the National Water Quality Objectives) over the next few years is examined with respect to mine environmental management practices. Some of the potential conflicts and changes in approach which may develop are identified and examples discussed. Proactive means of integrating trends in environmental legislation with mine planning and waste management are discussed.

Jan 1, 1994

By M Hilden, G Forbes, Z Ye, M Yahyaei, F Reyes, V Jokovic

Soft sensors offer several practical advantages for the process control of comminution circuits by combining multiple conventional sensors and other data sources with real-time analysis using mechanistic, phenomenological or machine learning models. While there has been a growth in the use of machine learning techniques for developing soft sensors in minerals processing applications, this paper describes advantages and challenges of using soft sensor models developed on the basis of process knowledge. Recent experience with three new soft sensor technologies developed by the authors are discussed. The Mill Filling Inference Tool which has been implemented at several mine sites, compares SAG mill load cell and power draw measurements with outputs of a semi-mechanistic power model to estimate the mill ball and total filling in real time. The progressive wear of the mill liners is modelled, allowing the model to correct the load mass due to the mass loss automatically and to estimate the charge trajectory. This information enables the mill to be operated more confidently near its limits. A coarse-ore stockpile soft sensor as been recently developed using a 3D cellular automata-based model to track ore size throughout the pile, and estimating the live capacity and size at each stockpile feeder to the primary mills. Finally, a hydrocyclone soft sensor is being developed to monitor performance using available hydrocyclone models to estimate the size and flow balance around the cyclone in real time. The model-based soft-sensor approach aims to synthesise and analyse existing data and provide operators and engineers with process- and model-relevant information that can facilitate making better process decisions. Maintenance data has proven useful for model development as it allows soft sensors to automatically adjust and compensate for the effect of progressive wear, for example for mill liners, thus helping the models to maintain calibration throughout the equipment life.

Aug 24, 2022

By V. Sheikhzadeh, M. Saghaeian, N. Esmaeili, R. Hejazi, A. Dehghani Ahmadabadi

High Pressure Grinding Rolls (HPGR) are mostly used prior to pelletising processes to increase the specific surface area (SSA) of iron ore concentrate. For expressing SSA, the Blaine index is utilised as one of the most important dimensional properties of iron ore pellet feed. ISO 21283 is a standard test method that explains the manual of Blaine air-permeability apparatus for determination of this parameter. In this standard, the disaggregation method is based on passing the minus of 1 mm samples from the 0.150 mm sieve. The disaggregation process has an effective role on the results of Blaine airpermeability test especially for regrinding HPGR products. In this research, firstly the Blaine index of samples was measured without disaggregation. Following this, disaggregation was done by passing the minus of 1 mm samples through three sieves with different dimensions, 0.150, 0.090 and 0.045 mm, separately, and the Blaine index was calculated for each one. Finally, lab-mill with rubber balls, called Jar mill, was investigated as another option. Screen analysis and image analysis with SEM were performed to evaluate the effects of the sample's disaggregation on the size distribution and agglomeration of samples. The results showed that the disaggregation method with sieve size 0.150 mm, according to ISO 21283, was not applicable for HPGR products because the particles were still stuck together. In addition, the disaggregation method with the sieve size 0.045 mm or with Jar mill offered reasonable results. Keywords: Disaggregation, Blaine index, specific surface area, regrinding HPGR, ISO 21283, Jar mill

Jan 1, 2020

By Jack Haptonstall

INTRODUCTION The mines of western central Mexico historically contributed a profusion of gold and silver for the treasury of Spain and later provided sources for financing the Mexican War for Independence and the Mexican Revolution. The western coastal and barranca (cliff) tribes were hunters and extremely hostile, and the Spaniards were not able to penetrate many of the rich districts of their rugged homeland until the mid-1700's. This was more than 200 years after Cortez began the Inquisition by defeating the Aztecs and their allies in a decisive battle in the great city of Tenochtitlan (present day Mexico City). The Spaniards had a voracious appetite for silver and gold, and it was inevitable that they would finally subdue the natives and commence mining activities. Described in this paper are some of the precious metal mining activities in the southern half of the State of Sinaloa and the western half of the State of Durango (Figure l), and specifically those mining activities in the area controlled by the company with which the author was associated for 14 years, Minas de San Luis, S. A. de C. V., the parent company of which is now Industrias Luis Min, S. A. GENERAL DESCRIPTION Geography, Logistics and Climate The most spectacular of the physiographic provinces, the western Sierra Madre Occidental is the cliff or "barranca" province, the

Jan 1, 1983

In most States of Australia it is a legislative requirement for underground mines to have a separate means of egress from the normal means of ingress to permit the safe evacuation of workers to the surface in event of an emergency. Such egress may be in the form of a ladderway equipped shaft/underlie or trafficable incline/decline. Additionally, there is a general requirement to have one or more airways, separate to the main shaft or other principal entrance of an underground mine, extending to the lowest level to permit ventilation to all parts of the mine. Fulfilling these requirement is difficult in the development phase of a mine when access underground is achievable by only a shaft or decline in the process by being sunk. What is frequently practiced in Australia is for production to then commence, sometimes in association with continuing development, in the same configuration without the establishment of this separate method of egress to the surface nor additional airway/s with reliance on refuge chambers to cater for back up in any emergency. Not only, could this jeopardise the health and safety of workers in case of an underground emergency it could be construed as a statutory breach of legislation. While recognising that refuge chambers are often used throughout underground operations nowadays their equipping and the criteria for their location needs to be bought into focus. This presentation discusses how such legislative requirement can be met alongside the use and appropriateness of refuge chambers.

Jan 1, 1998

By D. J. Pyra, J. Kudelko, Korzekwam W.

Polkowice region (Lower Silesia, Poland) is an area, where the copper mining activity started about 40 years ago and new technologies were applied. There are 3 underground mines, 3 processing plants, tailings pond (the biggest one in Europe), pipelines for flotation waste transport, railways. Although new technologies were applied during the copper ore exploitation, the environment in this area were polluted mostly by dust containing copper, lead, zinc and arsenic. Estimated values of heavy metals in polluted soils were compared to the natural contents of this metals. The geochemical background for Polkowice area was defined. The pollution zones occur around mining facilities. Copper ore exploitation and processing is planned for the next 20-40 years depending on market situation. After mines and other facilities closing the most important problem will be sustainable development of this area. To evaluate the scope of revitalization activities the analysis of recent soil environment condition will be necessary as well as forecasts for pollution migration. Geostatistic methods used also in mining will be very helpful for this task.

Jan 1, 2005

By Paul Armstrong

THE first discovery of lead and zinc ore on Calumet island was made in 1893 by John Lawn, who then staked a portion of the property now owned by Calumet Mines, Limited. His discovery was developed by James and Calvin Russell, who are said to have shipped a few tons of sorted ore, averaging 39 per cent zinc, 13 per cent lead, and 11 oz. silver per ton. In 1898, the property was being operated by the Grand Calumet Mining Company, who mined and shipped, for treatment in a Belgian smelter, 1,100 tons of ore averaging 32 per cent zinc, 9 per cent lead, and an unreported content of gold and silver. After some indecisive exploration by an American syndicate in 1907, the property lay idle until1910, when the Calumet Metals Company-later reorganized as the Calumet Zinc and Lead Company-re-commenced exploration. After sinking an 85-foot shaft-the McDonald shaft-and doing a few hundred feet of drifting and cross-cutting, this Company, in 1912, erected a 150-ton daily capacity gravity-concentration plant, in which some 800 tons of ore, mined from the McDonald shaft and Bowie pit, were milled. Owing to very disappointing mill recoveries, the property was shut clown and-after several years of idleness-in? 1916 the mill and mining plant were destroyed by fire and the Company went into bankruptcy. In 1918, an unknown operator shipped to an Omaha, Nebraska, smelter 22 tons of ore, probably sorted from the dumps of the Ste. Anne shaft and Galena pits, averaging 44 percent lead, and 0.26 oz. gold and 61 oz. silver per ton. The British Metals Corporation (Canada), Limited, in 1926, optioned the property. They unwatered the McDonald shaft and, after doing an additional 300 feet of cross-cutting and drifting on the 85-ft. level, estimated there were some 33,000 tons of ore between this level and the surface. Surface exploration, including trenching, on other showings on the property gave discouraging results and the option was dropped.

Jan 1, 1941

By M. M. Fine

Chalcocite flotation concentrates (26-34 percent Cu and 6-7 percent S) were roasted in air to determine sulfur elimination as a function of temperature, airflow rate, and residence time. Fluosolids roasting was evaluated batchwise and continuously in a 4-inch fluid-bed reactor. Kiln roasting tests were carried out in a 4-inch ID by 6-inch-long rotary drum. Pelletizing the very fine concentrates prior to roasting was essential to minimize dust losses and accretions. Concentrate pellets, sized minus 10 plus 20 mesh and bonded with 2 percent bentonite, were excellent feed for fluosol¬ids roasting and limited dust losses to 10 percent or less. One-fourth-inch pellets were best suited to kiln roasting. Both techniques were capable of producing copper calcines analyzing well under 1 percent residual sulfur when operated at 900° C with average retention times of 3 to 4 hours. Calcined pellets were strong, porous, and readily reducible.

Jan 1, 1970

By Allan D. Taylor

INTRODUCTION From the designer's view, the installation starts with the first definition of the orebody, and progresses through a long and complex development. The design is affected not only by the characteristics of the ore, but by all of the personalities and events of the project during its development. The following discussion attempts to touch on the most important aspects which define the context in which the designer must work in apply the do's and don'ts. That context is the basis of the viewpoint. WHAT CAN GO WRONG The Project Is Going Over Budget This is a common and serious concern to the plant designer. The Project Falls Behind Schedule Another common and disturbing condition with which the plant designer must cope. Some Equipment Fails to Perform This can be due to either faulty equipment or operating deficiencies. It can be the result of a wide variety of causes, but the designer will be an interested party in the search for the cause and the cure. The Plant Isn't Flexible Enough Sometimes a plant will handle some or even most of the ore satisfactorily but is unable to treat another type properly. This can be a significant problem. An example might be a case where low capacity of a cyclone feed pump makes it impossible to accompany an increase in grinding mill throughput with a corresponding increase in dilution water. This could lead to an increase in cyclone feed density, and a loss in product grade or a limit on the plant capacity. Spillage And Cleanup Are Excessive This is one of the most common and annoying defects in metallurgical plants, and one for which the designer can rarely delegate blame. Maintenance Is Excessive Another common complaint in new plants, and also one for which the dedesigner must accept most of the responsibility.

Jan 1, 1982

By J. J. Beresford

The primary function of a support slurry is to provide stability during excavation. Today foundation structures can be designed around the additional friction afforded by the absence of the filter cake attributable to the use of polymeric fluids as support slurries. These fluids use pseudoplastic fluid viscosity to advantage over the fragile thixotropic gel structures of bentonite. Many of today's polymeric fluids are environmentally acceptable for disposal directly to municipal sewers.

Jan 1, 1989

By J. F. Barkley

Under the procedure of the American Standards Association, with the American Society for Testing Materials as sponsor, the Sectional Committee on Classification of Coals has arrived at the classification of coals by rank as shown in Table 14/. The standard explains the term "agglomerating" used for classification under physical properties, as follows: Agglomerating Index. - Coals which in the volatile-matter determination produce either an agglomerate button that will support a 500-g weight without pulverizing, or a button showing swelling or cell structure, shall be considered agglomerating from the standpoint of classification.***. Pending the adoption of a method by the American Society for Testing Materials, the coke-button grading test5,/ afforded by the examination of the residue in the platinum crucible incident to the volatile matter determination, shall be used.

Jan 1, 1937

By J. O. Lewis

The operation of gas-condensate fields is comparatively new and involves physical principles with which the industry was not prcviously familiar. It has been necessary to devise methods for testing gas-condensate wells and to correlate laboratory and field data. In this paper new methods are advanced for interpreting well G.P.M.† tests whereby dilution by dry gas can be estimated and information supplied on revaporization of condensates by dry gas. Inaccuracies in well test data are discussed. Changes in flow rates can cause changes in the G.P.M. of the effluent and it may take some time for a well to become stabilized after an important change in flow rate. Retrograde tests as usually conducted cannot be directly compared with field G.P.M. data, because the retrograde tests usually include solution gas in the condensates, which are reported On the cumulative basis whereas field data (G.P.M.) usually report pentaneS PlUS on a rate or instantaneous basis. Introduction Though long known to physicists, the phenomena Of retrograde condensation became known to the oil and gas industry Only in recent years, when deeper drilling disclosed that the behavior of vapors under changing pressures was different in high-pressure reservoirs than under the low-pressure operations with which the industry was familiar. These deep, high-pressure reservoirs in which condensation and vaporization behaved inversely to the accustomed manner became known as "gas-distillate," or preferably "gas-condensate" fields. Partly to prevent precipitation and retention of liquids in the reservoir, but still more to prevent the waste of residue gas, the operation known as "recycling," or preferably "cycling," was instituted, in which the residue gas is reinjected into the reservoir, thus maintaining pressure and driving the wet gas to the producing wells. For lack of field experience to serve as a guide, the industry had to assume that theory and laboratory experiments could accurately forecast retrograde behaviors in operating these gas-condensate fields, but it is obvious that these assumptions should be checked at the first opportunities against actual field experience. To make such checks, it is necessary to accumulate a large quantity of reliable field data, but experience has shown that it is difficult to obtain reliable field data and that the laboratory data as usually presented are not in directly comparable form. The problems of correlation involve the complex phase behavior on the one hand, and a knowledge of field data and a visualization of underground conditions on the other hand. This paper is an approach from field experience, The purposes of this article are to discuss the sources of uncertainty in the data and to present methods of analyzing, interpreting and correlating laboratory and field data. Data mostly from lower Gulf Coast fields are presented, from which some conclusions can be derived, but better data from more sources than those available to the writer will be required before satisfactory answers to many questions can be obtained. This paper is presented to stimulate the analysis and publication of data from other fields, the reexamination of field and laboratory methods, and the taking of more complete and reliable field tests. For these purposes, the writer presents some speculations that otherwise would not be appropriate.

Jan 1, 1947

By J. O. Lewis

The operation of gas-condensate fields is comparatively new and involves physical principles with which the industry was not prcviously familiar. It has been necessary to devise methods for testing gas-condensate wells and to correlate laboratory and field data. In this paper new methods are advanced for interpreting well G.P.M.† tests whereby dilution by dry gas can be estimated and information supplied on revaporization of condensates by dry gas. Inaccuracies in well test data are discussed. Changes in flow rates can cause changes in the G.P.M. of the effluent and it may take some time for a well to become stabilized after an important change in flow rate. Retrograde tests as usually conducted cannot be directly compared with field G.P.M. data, because the retrograde tests usually include solution gas in the condensates, which are reported On the cumulative basis whereas field data (G.P.M.) usually report pentaneS PlUS on a rate or instantaneous basis. Introduction Though long known to physicists, the phenomena Of retrograde condensation became known to the oil and gas industry Only in recent years, when deeper drilling disclosed that the behavior of vapors under changing pressures was different in high-pressure reservoirs than under the low-pressure operations with which the industry was familiar. These deep, high-pressure reservoirs in which condensation and vaporization behaved inversely to the accustomed manner became known as "gas-distillate," or preferably "gas-condensate" fields. Partly to prevent precipitation and retention of liquids in the reservoir, but still more to prevent the waste of residue gas, the operation known as "recycling," or preferably "cycling," was instituted, in which the residue gas is reinjected into the reservoir, thus maintaining pressure and driving the wet gas to the producing wells. For lack of field experience to serve as a guide, the industry had to assume that theory and laboratory experiments could accurately forecast retrograde behaviors in operating these gas-condensate fields, but it is obvious that these assumptions should be checked at the first opportunities against actual field experience. To make such checks, it is necessary to accumulate a large quantity of reliable field data, but experience has shown that it is difficult to obtain reliable field data and that the laboratory data as usually presented are not in directly comparable form. The problems of correlation involve the complex phase behavior on the one hand, and a knowledge of field data and a visualization of underground conditions on the other hand. This paper is an approach from field experience, The purposes of this article are to discuss the sources of uncertainty in the data and to present methods of analyzing, interpreting and correlating laboratory and field data. Data mostly from lower Gulf Coast fields are presented, from which some conclusions can be derived, but better data from more sources than those available to the writer will be required before satisfactory answers to many questions can be obtained. This paper is presented to stimulate the analysis and publication of data from other fields, the reexamination of field and laboratory methods, and the taking of more complete and reliable field tests. For these purposes, the writer presents some speculations that otherwise would not be appropriate.

Jan 1, 1947

By C. C. Merrill

The Bureau of Mines beneficiated the wastes generated by commercial titanium chlorination operations to reclaim metal values and reduce the problem of disposing of solid wastes. A water leach solubilized about 40 percent of the dry weight and over 75 percent of the metallic impurities. The residue from the water leach was rich in titanium dioxide and carbon; it was combined with rutile and recycled to a laboratory chlorinator. The contained carbon was used in lieu of part of the coke requirement.

Jan 1, 1969

By M. A. Schellhardt

The Bureau of Mines has made periodic back-pressure tests on numerous gas wells in the Texas Panhandle field during the past several years to study the delivery capacities of the wells under different pressure and operating conditions and to determine the relationships between pressures and rates of delivery from gas wells.4/ However, information regarding the intake capacities of gas-well systems is meager, end in projects involving the flow of gas into porous-rock reservoirs it has been necessary to determine intake capacities of gas wells by trial. Accordingly the fundamental intake characteristics of natural-gas yells have been studied to develop a method for determining intake capacities under different wellhead pressures from data descriptive of the "output" or producing characteristic of the wells.

Jan 1, 1936