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By Shawna Von Stockhausen, Hong Yang, Tung T. Vu, Derek Penrice, Kevin Huynh

"The Regional Connector Transit Corridor is a 1.9 mile long light rail transit project in downtown Los Angeles, California. The project includes approximately 4,930 feet of twin bored tunnels together with a mined crossover cavern, 3 deep stations, and other cut-and-cover structures. The bored tunnels will be excavated using an earth pressure balance tunnel boring machine through Fernando Formation (extremely weak to weak rock) and alluvium. The tunneling will be performed in close proximity to a large number of existing structures, including the existing Metro Red Line tunnels with as little as 6 feet of separation. Thus, the evaluations of the tunneling effect on these structures and the instrumentation and monitoring program is an essential part of the project design. This paper provides a very brief overview of the considerations and evaluations of the tunneling effects on the existing structures and results of evaluation obtained during the final design stage of the project. INTRODUCTION The proposed Regional Connector Transit Corridor (RCTC) project provides a 1.9 mile-long connection between the Metro Gold Line from Pasadena and East Los Angeles; and the Metro Blue Line to Long Beach and the Expo Line to Culver City. The alignment is shown in Figure 1. The Regional Connector will provide new tracks through downtown Los Angeles. The project will extend underground from the Metro Blue, Expo, Red, and Purple Lines’ 7th Street/Metro Center Station following Flower Street, curving northeast to the north of 3rd Street under the 2nd Street Tunnel. The alignment will then continue eastward under 2nd Street, turning northeast to cross under the intersection of 1st and Alameda Streets, then splitting into two branches above the ground surface, one branch extending north along Alameda Street and the other extending east along 1st Street. The project elements include 3 deep stations, a SEM cavern, segments of TBM bored tunnels, and cut-and-cover guideway structures. The bored tunnels have an excavated diameter of 20.3 feet. The subsurface conditions along the tunnel alignment generally consist of artificial fill overlaying finer-grained alluvium (dominantly medium dense to dense sandy soils), underlain by coarser-grained alluvium (a wide variety of medium dense to dense sandy and gravely soils). Below the coarser-grained alluvium is Fernando Formation, which is characterized as extremely weak to very weak sedimentary bedrock. A long stretch of the alignment will be excavated in this formation. The soil layers above the Fernando Formation are of variable thickness and spatial distribution. The geologic profile is shown in Figure 2."

Jan 1, 2016

By T. D. Kaufmann

When Dr. David Gully solicited this paper last spring a few questions basic to commodity trade between the U.S. and world markets appeared perplexing. Why, for example, when the demand for aluminum was at a peak and when little expansion of capacity had taken place, was the dollar price half of what it had been at the previous peak? Or, why in 1984 when imports surged by 50% as the U.S. economy pulled out of its recession did the dollar not fall, but rather rose by 35%? And, why when the experts all seemed to agree that the dollar was grossly overvalued did the price of gold continue to decline? Surely these were extraordinary times for the mineral economist. When this paper was written in late July, 1985 the answers seemed clearer. The prices of many commodities were not low - the dollar in which they were denominated was too high. In other currencies many commodity prices were indeed high. The dollar was overvalued in trade terms by some 40% caused by an influx of short term coupon investments made by foreign money managers to take advantage of the higher short term interest rates in the U.S. relative to other international banking centers. With a decline in the relative difference in interest rates, an unhealthy buildup of foreign bank accounts and a perception that the dollar would fall, the dollar did start to decline rapidly.

Jan 1, 1985

By J. Astier

The idea of using only one strand for both sintering and cooling of the sinter is not new. In 1952, in the U.S.A. a sintering plant was built at Benson Mine (Star Lake, N.Y.), including : - 68 m2 or 735 sqft (8 wind boxes) for sintering, - 22 m2 or 237 sqft (3 wind boxes) for cooling. In the USSR, a large number of machines have been built allowing for cooling of the sinter on the strand, especially the 4 m (about 13 ft) machines, with : 252 m2 sintering grate area 60 m2 cooling grate area 312 m2 total grate area. However, such ventures did not prove very successful, and the IRSID embarked many years ago on a research program to discover : - what are the problems associated with cooling on a sintering strand ; - what are the possible solutions for industrial plants.

Jan 1, 1974

By Thomas L. Mell

Continuous processing plants handling liquids have achieved a high degree of centralized automatic control. Many chemical plants are operated from one room, with automatic control of the various process flow rates. These plants know from experience that automatic control can produce higher through-put, better uniformity of product, decreased operating costs and reduction of storage capacity, Plants which process materials in the form of bulk solids have not been able to use control to as great an extent, primarily due to the lack of measuring equipment capable of providing the same types of continuous automatic control available with liquid flow meters. This paper will describe a scale for measuring flows of bulk materials on conveyor belts which is particularly adaptable to remote centralized instrumentation and automatic control, and will also describe some typical control applications. Fig. 1 illustrates the basic method of measurement of this scale. A conveyor belt idler is supported on a rigid carriage which in turn is mounted in two anti- friction bearings on the conveyor stringers. The pivoted carriage is prevented from rotating about the pivot shaft by an electric strain gauge load cell connected between the carriage and a cross support. Increasing load on the conveyor belt increases the moment of the carriage frame about the pivot shaft, and proportionally increases the tension in the load cell. The belt speed is measured by a conventional d. c. tachometer generator driven from a pulley, usually on the return belt. The speed signal from the tachometer generator and the load signal from the load cell are combined to produce a signal proportional to the flow rate of material in tons per hour, or lbs. per foot, or equivalent units, It will be important to remember, in considering various control applications, that the flow rate of material on the belt is composed of these two component signals, namely the weight of material and the speed at which it is moving. The feed rate is then indicated and recorded by a self-balancing potentiometer of the type used for measuring temperature by means of thermocouples. These instruments may also be equipped with integrating mechanisms reading the totalized tonnage over a period of time.

Jan 1, 1958

By Angus Campbell, Michael J. Gobla

Numerous techniques for treating, controlling, and preventing acid rock drainage have been applied at the Summitville Mine Superfund Site. Challenging aspects of the remote mine site include the wide-spread occurrence of acid-generating soils and rocks, extensive surface and underground mine workings, and a cold and wet climate. Water treatment was an immediate necessity when the Government took control of the abandoned site in December of 1992. Subsequent reclamation activities have emphasized prevention and control of ARD to minimize future water treatment requirements. A combination of conventional, innovative, and experimental methods are being applied to successfully mitigate ARD at Summitville.

Jan 1, 2000

By Andrew L. Mular, Richard R. Klimpel

Optimization strategies of possible interest to mineral processing are reviewed and typical strategies initiated in processing plants to date are discussed. Both On-Line and Off-Line optimization procedures have been employed by industry, assisted either by operators or by digital computers. In every case, dollar benefits have accrued.

Jan 1, 1991

By R. Q. Phillips

INTRODUCTION Since Canada commenced sulphur exports in the early 1960's, the volume of exports has grown steadily and by 1984 Canadian sulphur accounted for 45% of internationally traded sulphur. In 1984 a total of 7.6 million tonnes of Canadian sulphur was shipped to offshore markets and the U.S.A. Total shipments, including domestic sales, were 8.3 million tonnes. With a production of some 5.6 million tonnes, inventory was drawn down by nearly 3 million tonnes in order to keep pace with demand. Since 1979, world consumption has exceeded total world production and Canadian sulphur inventory has played a truly crucial role in balancing world supply and demand. Consequently, by the end of 1984 the Canadian inventory, which stood at 21 million tonnes in 1978, had been almost halved to 12 million tonnes. This inventory, however, is still by far the largest in the world and will continue to play a vital role in the world supply until expected depletion around 1990. Canada is the world's second largest producer of sulphur following the U.S.A.. The Current production level of between 5 and 6 million tonnes per annum is forecast to be maintained to 1990 with only a marginal fall in that production level in the following decade to the year 2000. This will ensure that Canada retains its position as one of the largest producers and most important suppliers of sulphur in the world market well into the future. CANADA AS WORLD SUPPLIER OF SULPHUR Since Canada commenced sulphur exports in the early 19601s, exports have grown steadily. (Figure 1) The rate of growth accelerated in recent years and in 1984 a total of 7.6 million tonnes was sold for export, compared to 3.0 million tonnes in 1975 and less than 1 million tonnes in 1964. World trade in sulphur also increased during this period, from 11 million tonnes in 1975 to 17.0 million tonnes in 1984 (Figure 2). Most of this increase in volume was accounted for by Canada and Poland. As a result, the importance of Canada as world supplier expanded from 28% in 1975 to 45% in 1984. The markets for Canadian sulphur can be divided into two broad categories, i.e., solid and liquid (Figure 3). The solid market is the largest, taking about 70% of Canadian output, virtually all of which is sold offshore. The U.S.A. and the Canadian domestic market take about 20% and 10% respectively, in liquid form. In 1984, (figure 4) total Canadian sulphur sales exceeded 8 million tonnes with offshore export sales at a record 5.8 million tonnes and sales to the U.S. of 1.8 million tonnes. Domestic sales accounted for only 0.7 million tonnes. The general trend for offshore export sales has been upward whereas there has been relative stability in domestic sales. The exceptional growth in offshore sales in the 1970's necessitated considerable capital investments by the industry in order to establish a logistics system capable of handling increasing offshore tonnages. Over 50 sulphur plants are currently operating in Alberta and British Columbia. Some of these are connected by rail, (Figure 5) the balance being generally connected by road. There are currently fourteen of the larger rail-connected plants designated as export plants, and these are equipped with sulphur forming facilities. The long distances between these plants and tidewater terminals in Vancouver is a very significant factor in complex logistics of Canadian offshore sulphur exports (Figure 6). Alberta and B.C. plants are located an average of 1,400 kilometers from tidewater.

Jan 1, 1986

By Burke Trafton

An earlier paper1 introduced a rapid solution for mine ventilation network problems, employing the digital computer. In this paper, refinements and additions to the computer program which expand its scope of application and a solution to a ventilation network having a coal-mine configuration are presented. Specifically, the revised program--written in FORTRAN for the IBM 7074 computer in Penn State's Computation Center--is applicable to any mine ventilation network employing natural splitting and having its fan located externally. It accomplishes the following; 1. Distributes an assumed total quantity of air flow among all air- ways of the network, performing iterations until an acceptable level of error is attained and the flow in each airway is known. 2, Computes the pressure drop (head loss) in all airways and the overall network and mine head losses. 3. Determines the operating point for the mine and a given fan, adjusting all air flows and head losses to the actual values.

Jan 1, 1964

By Joel K. Waterland

GENERAL DESCRIPTION Homestake Mining Co.'s operations are at Lead, SD. Production from the various methods used are: 1 155 753 t/a (1,274,000 stpy) by open cut-and-fill, 68 039 t/a (75,000 stpy) by square set cut-and-fill, 144242 t/a (159,000 stpy) by shrinkage stoping, 107 048 t/ a (118,000 stpy) by blasthole stoping, and 67 132 t/a (74,000 stpy) in development work for a total of 1 542 214 t/a (1,700,000 stpy). Mining takes place from the 616-m (2000-ft) level to the 2073-m (6800 ft) level (Fig. 1). The average travel time to the stope is 45 min. GENERAL ORE BODY REQUIREMENTS AND LIMITATIONS Size, Shape, and Dip of Ore Body Six major ledges varying from 914 m (3000 ft) long by 228.6 m (750 ft) wide to 305 m (1000 ft) long by 122 m (400 ft) wide are mined. Within these ledges are irregular-shaped areas of varying sizes. These ledges dip at approximately 1.2 rad (70°) to the east and plunge to the south from 0.26 to 1.57 rad (15° to 90°). Ground Conditions The ore is cummingtonite (chlorite schist) which is very competent except for major bedding planes and fracture patterns. The footwall is a slate but because of the dip presents very few problems. The hanging wall is also a slate which because of the dip and bedding is very weak and requires considerable rockbolting. No problem has been encountered with rock bursts to a depth of 2438 m (8000 ft). Ore Value The ore values vary somewhat from ledge to ledge, but the average ore delivered to the mill is approxi¬mately 6.2 g (0.2 oz) of gold per ton. A small amount of silver is the only byproduct of this operation. Annual production of gold is approximately 10 575 183 g (340,000 troy oz). Production Requirements The mine has a mill capacity of approximately 1 723 651 t (1,900,000 st) but because of several fac¬tors (manpower, depth, etc.) this mill capacity has not been attainable for the past several years.

Jan 1, 1982

By I. K. Kapageridis

Digital photography combined with three dimensional models of topography, mining operations and restoration plans can lead to extremely realistic images and animations of the current and future states of a mine or quarry. The amount of work and the time required for the successful modeling of a mine and its restoration plan are surprisingly low nowadays. All this means that the visual impact of mining and quarrying operations can be easily assessed using common computer hardware and some dedicated software packages. LAVA Mining and Quarrying SA is a company committed to strive continuously for the highest possible environment protection at the company?s quarries. The pozzolanic rock quarry located at Xylokeratia is one of the company?s quarries on the island of Milos and the subject of the study presented in this paper. A thorough restoration plan of the Xylokeratia quarry is being completed by the company. For its purposes, a complete visual impact assessment study was performed at the Department of Geotechnology and Environmental Engineering of the Technological Education Institute of Western Macedonia. The procedures used in this study and the produced visual results are presented in this paper.

Jan 1, 2006

By Patrick Browne

Drilling programs and the study of active geothermal systems have shown that the reservoir rocks in many fields contain minor quantities of base and precious metals. Commonly, base-metal sulfides occur in the subsurface but, where present, Au, Ag, Hg, As, T1 and Sb rich precipitates deposit near, or at, the surface. Although in some fields (Geysers, Larderello, Tongonan) some of the ore minerals (and others) are relict, there is evidence that they are now depositing in a few systems. Recent work on active hydrothermal systems in New Zealand shows that: (1) Sphalerite, galena, chalcopyrite (forming veins and disseminated discrete crystals) plus rare pentlandite, cobaltite and arsenopyrite, occur at Broadlands, NZ. Rare quantities of base-metal sulfides also occur in cores and cuttings from the geothermal fields of Waiotapu, Kawerau, Tauhara, and Ngawha. Further, Kakimoto (1983) has identified cassiterite, native silver, and trace gold in cores from Tauhara, in the south-eastern part of the Wairakei field. Bore temperatures at the depths from which these minerals were recovered are mostly between 220° and 300°C, but at Broadlands are locally as low as 120°C. The host rocks are Quaternary talc-alkali, silicic lavas and pyroclastic rocks, andesites, dacite and deep Mesozoic greywackes and argillites; however, there is no obvious relationship between mineralization and stratigraphy, permeability or well output. (2) The deposition of amorphous precious metal precipitates (Au, Ag, Hg, As, Sb, T1) from hot springs and well discharges has taken place at Broadlands, Waiotapu and Rotokawa; it also occurs at Kawerau. (3) Water discharging from Frying Pan Lake, Waimangu, is presently depositing siliceous sinter containing up to 4.1% tungsten. A characteristic of mineral-depositing fluids in the New Zealand geothermal fields is their very low salinity (total dissolved salts of 3000 ppm or less but with high CO2); they are of near- neutral alkali chloride composition, although water discharging from Frying Pan Lake has a pH of 4.5, and very low metal contents. Very effective concentration processes (10 times for gold at Broadlands) must occur: in the subsurface these include boiling and rapid cooling but near, and at, the surface, mixing of waters of different pH seems to dominate. In particular, descending acid condensate, derived from separated steam and oxidation of H2S mixes with its parent alkali chloride water, resulting in precipitation of amorphous ore metals. Base-metal sulfides also occur in veins and as disseminated grains in geothermal fields at Tongonan, Leyte and Southern Negros, Philippines. These fields have a porphyry-type setting with host rocks of Miocene andesitic lavas and pyroclastics intruded by diorites so that the fields have undergone complicated thermal histories before cooling to their present base temperatures of about 325°C. Precious metals have precipitated from waters from some wells (Leach, pers. comm.) but they do not, as yet, form ore-grade deposits.

Jan 1, 1984

By Donald L. King, Frank A. Baczek

Sedimentation-based equipment is used in applications where separation of solids from liquid by gravity settling is desired. If a concentrated solids slurry is desired, the equipment is designed to "thicken"; if a clear liquid is desired the equipment is designed to "clarify." Thickeners normally handle higher solids loading rates than clarifiers, which usually process feed slurries containing low concentrations of suspended solids. Thickeners are therefore designed for heavier-duty requirements, and clarifiers have extra features to ensure more complete suspended solids removal. Major components (Figure 1) that are common to all sedimentation-based equipment are: tank, drive-support structure, drive unit and lifting device, rake structure, feed well, and a means of overflow and underflow withdrawal. Specific features are designed interdependently after the overall separation approach is defined conceptually. This conceptual approach is usually based on past experience or evolves from sedimentation studies conducted on samples of the slurry to be handled. Because many variations and combinations of components are possible, the overall conceptual approach has a number of possible designs that will accomplish the desired results. The final choice is based on practicality, potential for minimizing upsets, and cost.

Jan 1, 1986

By M. T. Ityokumbul

Concentrate flowrates have been measured for the flotation of -100 mesh Lower Kittaning coal in a computer controlled 0.076 m x 3.5 m pilot flotation column. The variables studied were recovery zone height), air flow rate, and solid feed concentration. The size distribution of concentrate and tailings samples were determined. The results obtained show that the concentrate flow rate was independent of collection zone height, but dependent on the gas flow rate, solid loading and particle size. New correlations for column carrying capacity and yield are provided as a function of these fundamental operational parameters.

Jan 1, 1997

By Dell H. Adams

Coal exploration may be defined as the acquisition of data necessary to define and acquire a block of coal which can be mined at a profit. Unlike ore minerals, coal resources are widespread and relatively abundant with supply exceeding demand in almost every case. Thus simple discovery of coal is generally not enough. The chemical and physical variability of individual coal seams, the capital intensive nature of coal mine development, and the changing patterns of utilization require that a multiphase, three-dimensional evaluation be made of each potential reserve. Factors which must be investigated include not only the quantity and quality of the coal but also the geologic, hydrologic, and engineering characteristics of the seam and its surrounding strata. Acquisition of property to provide a secure base for exploration and mine development is equal in importance to the geologic and engineering programs. The successful development of a coal reserve requires that control of coal and, in the case of a strip mine, the surface be in the form of contiguous blocks of sufficient size to support mining.

Jan 1, 1981

By M. S. Klima

A 25-mm diameter dense-medium cyclone was tested to investigate the effects of geometry and operating conditions on cyclone performance when processing -150 I'm coal. The emphasis was on examining those variables (e.g., flow rate and inlet velocity) which impact the separation kinetics (specifically the number of g's and the mean retention time) and the occurrence of apparent bypass. Apparent bypass, indicated by partition curve "tails", results from the short circuiting of the feed coal to one or both of the product streams and represents a loss and/or contamination of the clean coal. This paper presents the results for this series of tests.

Jan 1, 1993

By L. A. Puchkov

The paper presents the outline of the results in the algorithms and software of the microprocessor-based system for the powerful drugline bucket automatic motion, as well as the technological process control and functional diagnostics of the electrical equipment. The system is, aimed at the increasing both the draglines' working efficiency and the professional, competence of the operators. The excavator-dragline, equipped by the automatized operation, diagnostic and information processing system, possesses considerable technological: flexibility, which can widen therefore its field of application. The tasks of the dragline bucket motion optimal operation, programming of the excavation and overburden dumping processes, as well as the tasks of the control and the analysis of the technological parameters and the diagnostics of electrical equipment conditions, are defined in the paper. In our paper we present the results of these tasks being solved, providing the algorithms of the main mechanisms for the automatic operation for the swinging bucket controlled motion, the algorithms of the statistical analysis of the working efficiency parameters the algorithms of the diagnostics for electrical driving systems. The algorithms of the motion operation are constructed using the predicting dynamic models. The diagnostic algorithms at the normal working conditions form a number of algebraic invariants always equal to Ø with the accuracy up to when the electrical equipment is parametrically adequate. The algorithms of evaluating and analysis of the excavation efficiency make use of the direct measurement and analytical identification. The working condition and quality of the operation and control algorithms are investigated by simulation and natural testing. The results of the mathematical simulation of the bucket motion (with the 20 m3 capacity) of the excavator-dragline with the boom of 90 m in length are given in the paper.

Jan 1, 1992

By G. S. S. Raman, M. S. Klima

The effects of pressure and cake thickness were studied using a split-plot design for pressure filtration of a fine refuse slurry obtained from a bituminous coal preparation facility. Pressure filtration offers the potential to significantly reduce the moisture content of the fine refuse stream with the addition of little to no flocculants, thereby minimizing the volume of refuse stored in impoundments and providing a recycle water stream for use within the plant. Experimental results showed that the final cake moisture decreased with increase in pressure and decrease in cake thickness. In addition, specific cake resistances calculated for the various tests indicated an increasing trend with increasing pressure and decreasing cake thickness. With increase in cake thickness, an increase in cake moisture and the weight of solids deposited in the cake was observed. An ANOVA analysis indicated that both cake thickness and pressure significantly affected the cake moisture, while only cake thickness statistically influenced the weight of solids in the cake. A regression model was developed with an R2 value of about 0.99 to relate cake thickness, the single largest statistically significant factor, with the weight of solids in the cake. Filter capacities were calculated in terms of the solids deposited per unit time based on a product specification of 25 percent cake moisture, and it was observed that the thinnest cake had the highest filter capacity.

By James R. Arnold, John G. Mansanti

BACKGROUND Gold Fields Mining Corporation started their Chimney Creek operation in late 1987. The dump leaching operations commenced in October and the mill startup took place during the last half of November. The milling process at Chimney Creek is almost a conventional CIP plant with the major exception being the installation of a second thickener as a washing stage prior to CIP12 ' A simplified flow sheet is shown in FIGURE 1. Most of the gold in the mill is liberated by grinding in cyanide. After grinding in a conventional SAGball sill circuit, the cyclone overflow reports to the thickeners. The thickener overflow from the first thickener is pumped through 5 stages of carbon columns for gold adsorption. Slurry from the thickener underflow is leached, washed, re-thickened and pumped to CIP. After approximately 6 hours of retention time in CIP, the slurry is pumped to tailings for final deposition. The carbon from CIP is transferred to the third stage of carbon adsorption and then advanced as normal through the columns and strip circuit. Loaded carbon is stripped at approximately 1500C (3000 F) and 55 kPa (80 psi). After 4-5 hours of stripping, the grade of four tons of carbon is reduced from 5,140-6,860 g/t (150¬200 oz/ton) to typically 17 g/t (0.5 oz/ton). Zinc precipitation is used to recover the gold from the pregnant solution. After a water wash, the stripped carbon is transferred to acid wash or to the kiln feed tank for reactivation. All strip lots are acid washed in 3.0% HC1 and all stripped carbon passes through the kiln for thermal reactivation. Then the carbon is quenched, sized and stored in tanks or bins for transferral to CIP or to the carbon columns. Loaded carbon from the dump leach circuit is treated in a circuit consisting of five carbon columns which are parallel to the mill circuit. No distinction is made between the mill or dump leach carbon once the gold has been stripped from them. CARBON FINES HANDLING Once the carbon has been transferred from the carbon columns, every effort is made to minimize carbon attrition and to recover the carbon fines that have been generated in the process. Wemco Hidrostall pumps are used for transferring all carbon in

Jan 1, 1990

By J. C. Squire, E. W. Baker, G. A. Sullivan, G. W. Flathers

A mine collapse severs communication with trapped miners. Landlines are crushed and commercially available radios cannot penetrate hundreds of feet of dense, conductive earth without the use of regenerative repeaters that may also be crushed. This paper describes a proof-of-concept device that uses seismic P-waves, instead of radio waves, to allow communication of a code that represents prearranged messages, including the safe haven location identifier, number of people and air quality, from trapped miners to aboveground rescue units. The transmitter designed is about 0.03 m3 (1 ft3) in size and can broadcast for four hours from its 27-kg (60-lb) battery pack. The receiver consists of a geophone and a 2.5-kg (5.5- lb) signal conditioning unit attached to a laptop computer, which displays the communication signal in real time. Testing in a bituminous coal mine with an MSHA representative revealed the device was able to transmit through 271 m (890 ft) of overburden, at 0° and 12° from vertical, using 500 W of power.

Jan 1, 2009

By Kirk Carlton

This paper deals with a group of subjects so familiar to all of us that we might question the need for discussion. Even so, nearly every day's business turns up expensive examples of differences in understanding, misdirected assumptions and incomplete technical purchase documents. As our international activities increase, so do these problem areas. Their expense in both money and embarrassment gives rise to this attempt to focus a little extra attention on technical criteria and specifications. The two terms ?criteria? and "specifications" are, we believe, worth separating with respect to meaning. They should not be used interchangeably, although they often are. Criteria are by definition "standards for judging", whereas specifications are "enumerations of particulars". In relation to plant or project engineering, the criteria are the general rules and data which apply to the whole project and the specifications are the further listing of detailed requirements for specific contractual items or pieces of equipment. We'll look a little more closely at specifications after we give another minute or two to this "criteria" subject,

Jan 1, 1973