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By H. P. van Ormer

The objective of this paper and the developed personal computer program is not to identify or try to identify the actual total drilling cost in any Rotary Drilled Blast Bole Program. The ideas put forth here and in the computer program developed are a very accurate way to measure what is often very hard to identify and interpret -The actual direct operating cost of various drilling package combinations including comparing with available blast hole sizes and patterns

Jan 1, 1988

By R. J. Sandberg

The Copper Creek area, part of the Bunker Hill District, Pinal County, Arizona, lies within the southwest porphyry copper province of North America at the intersection of a northwest trend and an east-northeast trend of Laramide porphyry copper deposits. The Copper Creek area has been mined and explored for copper and molybdenum since the early 1900?s. The majority of this work focused on the more than 400 surface exposed breccia bodies. In the 1960 to 1970?s deeper drilling discovered a deep porphyry copper-like setting. Redhawk Copper currently has NI 43-101 compliant resources of about 0.652 billion pounds of measured and indicated and 2.745 billion pounds of inferred copper equivalent in breccia hosted and porphyry style deposits. See Figure 1.

Jan 1, 2010

By Hans E. Tausig

The economics of transporting minerals by sea in less than full cargo lots encompasses an analysis of production costs, sale and inventory calculations and a careful comparison of ocean freight costs all of which when pieced together will usually definitively indicate which of the ocean freight alternatives is the correct one for the economic factors involved. To illustrate: Let us assume that a production to be marketed yields 60,000 metric tons of copper concentrates over a twelve month period. Shipment is geographically viable through Vancouver, B.C. The production has been sold to a Japanese Smelter and the mine produces at a rate of 5,000 metric tons of concentrates per month. The copper has been sold CIF FO. The Seller has carefully investigated ocean freight rates Vancouver, B.C./Hibi, Japan and finds that he could obtain a twelve month freight contract at $15.00 per metric ton FIGS based on a loading/discharging speed of 4000/ 2000 metric tons per WWDSHEX (weather working day, Sundays and Holidays excluded) this freight rate being predicated on shipping in lots of minimum. 15,000 tons. A further freight investigation reveals that to ship at the same terms and conditions but in lots of 5,000 tons, and shipping each month (in accordance with the mine's actual production) would cost $20.00 per metric ton FIOS. The calculation that is now made is whether it is more desireable to pay a higher ocean freight by shipping in 5,000 ton lots or to pay the lower freight where here the ocean freight involves a difference of some $300,000.00.

Jan 1, 1979

By Wen L. Chen

The steam coal quality is less stringent than metallurgical coal quality. The steam coal is prepared either by cleaning full size range of raw coal or cleaning coarse coal only, leaving the fine coal raw. The latter scheme is more cost competitive. It is particularly applicable to U.S. eastern soft coal where low ash coal is concentrated in fine sizes. For raw coal size separation, a recently developed Rotating Probability Screen, developed by the British Coal Board, may be advantageously used for easy change of raw coal separating size and to avoid screen deck plugging when handling wet and clayey raw coals.

Jan 1, 1983

Strainburst phenomena, generally characterized by a sudden release of energy in a volume of highly stressed rock, are often encountered in such situations like crown pillar bursts in cut-and-fill mining, face bursts at development headings and floor bursts in deep shaft sinking. This paper describes a simple FE modeling approach which leads to the calculation of the energy release rate (ERR) and the total energy storage rate (TESR) in the rock mass around the openings. The merits of using such energy parameters in the analysis of strainburst problems to identify areas of high energy release/storage are discussed. However, much site-specific back analyses are needed to better understand how strainbursts and energy parameters are inter-related.

Jan 1, 1998

By I. L. Jennings

In most industrialized countries, the largest element of the mining industry in physical volume is that devoted to the extraction and processing of materials for use as construction aggregates. Required for all developments in industry and commerce, power and transportation, and housing and public services, their use is so widespread that possible sources are exploited throughout all geographic regions, as close as possible to the point of use. Thus, it is also the most frequently encountered form of mining throughout the world. These materials come from four main sources:- (a) Excavation of unconsolidated deposits of sand and gravel (b) Stone quarrying. (c) Processing of slags and other mineral wastes. (d) Manufacturing from clays and shales by heat fusion. The major uses are in: (a) Portland cement concrete, that most versatile of construction materials, including the many concrete products in current use. (b) Asphalt cement concrete; widely employed for paving roads, parking lots, airfields, etc. (c) Foundation materials, such as road base, granular backfills, railway ballast, etc.

Jan 1, 1968

By M. Rodgers

Dow Water & Process Solutions (DW&PS) was approached by ASARCO Inc. to attempt to recover cobalt and copper from their copper solvent extraction (SX) raffinate. Cobalt is added to many copper electrowinning tankhouses to help to prevent lead electrode corrosion. With cobalt?s high price this can be a large expense. ASARCO has ore that contains a small amount of naturally occurring cobalt. Currently they have no way of capturing this high value metal from their leach or raffinate streams. DW&PS has some chelating resin technologies that should be able to help solve this problem.

Jan 1, 2010

By Peter W. Willcocks

The Cyanide Regeneration Process (CRP) was developed by Golconda Engineering and Mining Services and installed at Golconda's Beaconsfield Gold Tailings Retreatment Project situated in Tasmania, Australia. The Tailings Project is a 1000 ton per day carbon-in-pulp treatment plant, feed for which consists of tailings material which is dredged from the Tamar River. The pulp is screened to remove debris, then cycloned to form two products. Underflow pulp is stored in a 350 ton bin and cyclone overflow passes to a thickener. The coarse pulp material is fed to the grinding circuit then rejoins the thickened slimes in the cyanide leach circuit. Gold is extracted by carbon-in-pulp techniques. The plant is sited in rolling, hilly country approximately 200 meters from the Tamar River. The residue disposal area is quite small consisting of four dams, totalling 42 acres. The regional climate is cool and wet with little evaporation; therefore, we anticipated a net increase in contained liquor, and subsequent storage problems. Our plan was to remove cyanide from the liquor prior to returning the detoxified solution to the river system. Such treatment was not required until midway through the second year of the project. Initial testwork on sample material indicated that destruction of cyanide by chlorine was the simple solution. Subsequent follow-up on actual plant liquor indicated a huge chlorine requirement due, we believe, to the substantial degradation of vegetable matter plus organic content from the marine environment. The cost of cyanide destruction could not be justified.

Jan 1, 1998

By W. T. Plummer

• The SuperBowl is a fluidized bed, semi-continuous, enhanced gravity separator for gravity gold recovery. The market for this type of equipment has, until recently, been dominated by a single supplier. Many mineral processors have encouraged the SuperBowl designers to develop competitive equipment for obvious reasons. • The primary beneficiary of competition in this field will be the mineral processing community because legitimate competition fosters continuous improvement in product and price.

Jan 1, 1996

By Geoff Whebell, Dianne Coulthard

Sampling studies of high silver (+70%), gold dore led to the development of mine site sampling techniques and superintend­ing for the collection of samples for assay and bullion weights for settlement of shipped material. Data is presented which con­firms the reliability of the procedures against the traditional remelting and sampling at the refinery. The advantages to both mine and refiner are significant and are discussed.

Jan 1, 1998

By David A. Summers

Historically, the presence of methane has been a problem, mainly in and around the working areas of active coal mines, and only in these area has drainage been considered. Drainage, where practical, has been achieved through the drilling of holes forward into the coal and the surrounding strata from the working area. These holes generally have been short in length, although where methane drain- age operations around a longwall face have been undertaken, the holes have had to be longer in order to adequately drain from the center of the face into the access gate roads. In recent years, attempts have been made to degasify the coal seams in advance of mining, without disruption of the mining cycle. This is done by drilling much longer horizontal holes through the coal in advance of the working area. Under the aegis of the Federal Government, methods have also been developed for draining seams of coal of their methane content in advance of mining, but from shafts sunk from the surface, without using the active area of the mine as the location for the drill holes.

Jan 1, 1979

By E. J. Berentsen

The Turquoise Ridge gold deposit is located near the Getchell Mine, 72 km (42 miles) northeast of Winnemucca, Nevada. The deposit is owned by First Miss Gold Inc. The host rocks consist of Ordovician and Cambrian age shales and limestones. They have been crosscut by the northeast-trending Turquoise Ridge shear zone and northwest-trending shear zones. Gold mineralization occurs at depths from 427 m (1 400 ft.) to 671 m (2 200 ft.), along the intersection of these structures. Large tonnage, flat-lying deposits occur where folded, favorable beds are intersected by the faults. The carbonate within the beds has been replaced with silica, pyrite and arsenic sulfides.

Jan 1, 1996

By Harry R. Dahlberg

Heap leaching is discussed as a unit process. Five factors are identified as the principal elements that can be measured and/or controlled. These are: 1. Material Size 2. Volume of solution 3. Tonnage of heap 4. Time 5. Solution concentretion. The Rate of Extraction Curves obtained from an actual heap or column tests describes the economic viability of the unit process. By analysis of these curves and the five factors end their inter-relationship it is possible to determine how the extraction rate can be increased. The practice of leach and rest used by many operators is analyzed and shown on a hypothetical rate of extraction curve. The influence of the driving force of the hydrogen ion and ferric Lon as Lixivants and its effect on the rate of extraction curve is discussed.

Jan 1, 1979

By D. Suarez

The work of engineers responsible for the design and performance of mine facilities is often challenged by economic and practical constraints in the field. Problems have developed in implementing design criteria dictated by persons or agencies not familiar with the dynamic nature of mine engineering. Regional and site-specific conditions frequently require changes to standard designs, or the use of a completely innovative approach, which is not provided for in the regulations. The implementation of engineering design, therefore, usually requires a hard-sell approach to management and regulatory agencies that allows for a happy-medium to all parties concerned. Flexibility on the part of the regulatory agencies is needed to solve operational and environmental problems with sound engineering. Typical hydrologic issues which will be discussed fall in the following general categories: ? Design criteria for sizing water control structures (i.e., culverts, diversion and sedimentation ponds, ditches, etc.) ? Implementation (construction and operation) difficulties ? Regulatory compliance ? Reclamation planning with hydrologic considerations ? Protection of groundwater resources

Jan 1, 1986

By Peter Zhang, Daniel Su, Heather Dougherty, Jack Trackemas

"Longwall mining has a significant influence on gas wells located within longwall chain pillars. Subsurface subsidence and abutment pressure induced by longwall mining can cause excessive stresses and deformations in gas well casings. If the gas well casings are compromised or ruptured, natural gas could migrate into the mine workings, potentially causing a fire or explosion. By the current safety regulations, the gas wells in the chain pillars have to be either plugged or protected by adequate coal pillars. The current regulations for the gas well pillar design are based on the 1957 Pennsylvania gas well pillar study. The study provided guidelines for gas well pillars by considering their support area and overburden depth as well as the location of the gas wells within the pillars. As the guidelines were developed for room-and-pillar mining under shallow cover, they are no longer applicable to modern longwall mining, particularly under deep cover. Gas well casing failures have occurred even though the chain pillars for the gas wells met the requirements by the 1957 study.This study presents seven cases of conventional gas wells penetrating through longwall chain pillars in the Pittsburgh coal seam. The study indicates that overburden depth and pillar size are not the only determining factors for gas well stability. The other important factors also include subsurface ground movement, overburden geology, and weak floor, as well as the construction of gas wells. Numerical modeling was used to model abutment pressure, subsurface deformations, and the response of gas well casings. The study demonstrated that numerical models are able to predict with reasonable accuracy the subsurface deformations in the overburden above, within, and below the chain pillars, and the potential location and modes of gas well failures, therefore providing a more quantifiable approach to assess the stability of the gas wells in longwall chain pillars.INTRODUCTIONIn the eastern United States, abundant gas wells have been drilled through coal seams that are being actively mined by longwall mining. The existence of gas wells in the U.S. coal fields, whether active or abandoned, have caused many issues for longwall mining. First of all, any gas well in the mining area has to be located by all possible means. Secondly, the gas wells within longwall panels have to be plugged, as cutting through gas wells will allow natural gas to flow into the active longwall mines. On the other hand, the gas wells within longwall chain pillars or barrier pillars can be left in place if the wells are protected by properly designed pillars."

Jan 1, 2019

By W. M. Shaver, R. Letourneau, W. R. Dengler

Dynatec Mining Limited contracted to sink a 1500 metre (4960 ft.) concrete lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft is 6.3 metres (20.5 ft) in diameter inside the concrete lining and is equipped with steel furnishings. Dynatec used the owner supplied 4.6 metre (15 ft.) diameter double-drum hoist to sink the shaft with 12.5 tonne buckets for muck removal and 4 cubic metre concrete buckets for concrete placement. One of the unique features of the shaft sinking operation is the use of a four-boom electric hydraulic drill jumbo permanently mounted in the shaft sinking stage. This paper will describe the performance obtained with the electric hydraulic drilling equipment and the high capacity muck removal and concreting equipment.

Jan 1, 1991

By Donald S. Clarke

The Umuna epithermal precious metal deposit has provided the target for a simulated rock geochemistry exploration program, directed at bedrock exposed in the drainage system of eastern Misima Island. A geochemical halo to the deposit is readily recognised in the mafic meta-volcanic country rock. This halo is defined by anomalous results for both major (K, Na, Ca, Mg) and minor (Au, As, Sb, Cu, Pb, Zn, Ba, Rb, Sr, Cs, Bi, Ga, S) element geochemistry, extending further than 1km from the deposit. Such halos are sufficiently extensive to provide adequate exploration targets in the search for epithermal mineralisation, complementing mineralogic and secondary media geochemical investigations.

Jan 1, 1989

Room-and-pillar mining at White Pine started in 1953 from a sub-outcropping orebody that gently dips to 1000 m depths in a distance of about 6 km. High horizontal stresses were recognized in the mid-1960s which had obvious stability impacts when viewed in combination with the increased overburden stresses. Modifications in conventional room-and-pillar design were introduced through the years on a trial-and-error basis to help overcome stability and resource recovery problems. These modifications were based on pressure arch concepts using pillar yielding and/or pillar recovery, and on mine layout orientation to minimize stress impacts. While some of these modifications were successfully applied in some areas, they failed in others. Through the years, visual observations played a major role in panel design with contributions from stress measurements and analyses. However, the down slide in the copper economy during the 1970s and early 1980s resulted in a loss of interest in the application of these concepts. This paper reviews ground control problems and presents the results of recent stress measurements and computer analyses. They shed light on the importance of using yield pillars and mine layout orientation to control stresses at depth.

Jan 1, 1993

By Charles A. Hickey

The dining industry game tome Spruce Pine area a few years after tine Civil War. Two Yankees came down from Massachusetts to mine sheet mica to sell to the stove manufacturers for windows in heating stoves. At this time the method of mining was very crude; it was done only with pick and shovel. They were mining mica from the soft veins. Later they progressed to hand grilling and blasting. Hand drilling was quite an art in the area. One man would hold and turn the steel while one or two other men would drive the steel with hammers. In shaft raining, the muck and water was removed by hand winches called windlasses. About 1920 air compressors and jack hammers came into use. These were perhaps tide greatest improvement that has ever come to the area's mining industry. Later carne gasoline hoists, air drive water pumps, and all electrical equipment. Mica mining has, for the past few years, been very modern and efficient.

Jan 1, 1962

By K. P. Pavlich

Strategic planning, including the process of developing competitive strategy, is an integral part of all organizational management; from one person operations to multi-national Fortune 100 firms. The structure of that process varies from decisions and direction based upon one person's intuition to the integration of multiple strategic planning groups from each of a firm's many business units. Everyone has heard interesting strategic planning stories such as the railroad industry's long term failure to realize that they were in the transportation business and not the railroad business, the decision to "give away the razors and sell them the blades", Caterpillar's "SOQ NaP" campaign (Sell On Quality, Not On Price), or the tanker industry's eventual realization that by better managing turn-around the firm could control their largest single cost: depreciation. It is important to remember that very few strategic planning decisions are going to become Harvard Business Review case studies. That fact does not, however, diminish the need for understanding the firm's business, and actively planning how it is going to remain in business in the future!

Jan 1, 1989