Mineralogy

Stop Mining Method

Stop Mining Flat Deposit

In the previous topic you were introduced to the different methods adapted to mine underground deposits. Well the basic elements are common to most underground mining operations, there are many variations in the theme. In the next three topics we will see how these methods can be adapted to mining deposits in different geologic situations. stop mining method (1)Let’s start by looking at stope mining in flat deposits. In the previous topic we were introduced to strata form and stratabound deposits which are common from minerals such as coal and iron ore. Where these occur the flat deposits that is sloping at around less than 20 degrees. These lend themselves to a particular stall called stope mining. What is common today is that the mining progresses from one part of the deposit to another mostly within the same plain. What is different is the size and the shape of the pillars used to support the roof and the methods used form them. Stope mining and flat deposits are distinguished on the basis of the stall or the stake being merely described as rooms, stalls, or boards in ….Read more

Ammolite

ammolite

Ammonite is an iridescent gem formed within an ancient marine fossil for which it was named—ammonite. Originally discovered by the Blackfoot Indians, ammolite is mined only in Southern Alberta, Canada. Most ammolite is assembled into doublets or triplets to increase durability because solid ammolite is usually thin and fragile, If it’s untreated and solid, ammolite is usually priced per carat and shaped as a freeform to maximize weight.  Extra fine quality ammolites display three or more sharp, brilliant colors with no obvious dark areas except for fine lines which separate the patches of color. The narrower the lines the better. The most prized stones are those that exhibit the full color spectrum including blue and purple, which are the rarest colors, but ammolite with ….Read more

Mineral Identification by Spectroscopy

FIG. 35 gives an idea of the spectroscope and of its different parts. P is a flint glass prism, having a refracting angle of 60° and resting on a brass plate fixed on a brass support, S. The brass plate carries the collimator tube C, in the end of which nearest to the prism is fixed a lens, the other end being closed by a plate in which there is a vertical slit, which can be widened or narrowed as required by means of a small screw

The tube E has also on the end nearest the prism a lens, and at the other end a reduced photographic millimetre scale which can be seen through the telescope T. At the end of E is placed an ordinary gas burner, a little distance from the photographic scale. Right opposite the slit in the collimator tube C is placed an ordinary bunsen flame, in which the substance to be tested is placed in the loop of a platinum wire. E is adjusted so that the image of the illuminated scale can be seen through the telescope T, and the divisions are focussed by means of a small screw on E. All extraneous rays of light are ….Read more

Properties of Gold & Alloys

From very early times the ancients were attracted by the beautiful colour, the brilliant lustre, and the indestructibility of gold, and spared no pains in the endeavour to acquire it. In the code of Menes, who reigned in Egypt in 3600 B.C. or about 2000 years before Moses, the ratio of value between gold and silver is mentioned, one part of gold being declared equal in value to two and a half parts of silver, and it is, therefore, clear that the extraction of both metals from the deposits containing them must have been carried on before that time. It is, indeed, probable that gold was the first metal observed and collected, since it occurs in fragments of all sizes in loose sand, and the operations of collecting the larger pieces and melting them together are so simple. Among the rock carvings of Upper Egypt there are several illustrative of the art of washing auriferous sands by stirring and working them up by the hand in hollowed-out stone basins, and subsequently melting the gold in simple furnaces with the aid of mouth blow-pipes. The earliest of these carvings is supposed to date back to about 2500 B.C. However, in ancient ….Read more

Crystallisation of Gold

Gold crystallises in the cubic system, occurring frequently in nature in the form of cubes, octahedra and rhombic dodecahedra. Cleavage is never exhibited. Single detached crystals are comparatively rare, and the crystals are usually attached end to end, forming strings, and branching, arborescent, or moss-like masses, which are composed of microscopic crystals, usually octahedra. These forms occur frequently in quartz veins, but the single crystals, which are usually of larger size—viz., from ¼ to 1½ inches in diameter — are mainly found in drift deposits. They are rarely perfect or of brilliant lustre, although such crystals were found at the Princeton Gold Mine, Mariposa County, California, but occur more frequently with rounded angles, raised edges, and cavernous faces, which are often marked with parallel striations, and possess little or no lustre (Fig. 1). The octahedra found in California are usually flattened parallel to two opposite faces, or elongated, or otherwise distorted. Still more frequently they are only partially developed, as in Figs. 2 and 3. In all these cases “ the incomplete crystals have the appearance of a failure for lack of material” (W. P. Blake). Crystals of greater complexity, containing many modifying faces, occur chiefly in Siberia, Transylvania, and Brazil. ….Read more

Descriptive Mineralogy Classification

Scope of Descriptive Mineralogy. — It is the province of Descriptive Mineralogy to describe each mineral species, as regards: (1) form and structure; (2) physical characters; (3) chemical composition including blowpipe and chemical tests; (4) occurrence in nature with reference to geographical distribution and association with other species; also in connection with the above to show how it may be distinguished from other species. Further, it should classify mineral species into more or less comprehensive groups according to those characters regarded as most essential. Other points which may or may not be included are the investigation of the methods of origin of minerals; the changes that they undergo in nature and the results of such alteration; also the methods by which the same compounds may be made in the laboratory; finally, the uses of minerals as ores, for ornament and in the arts.mineralogy

Scheme of Classification. — The method of classification adopted in this work, and the one which can alone claim to be thoroughly scientific, is that which places similar chemical compounds together in a common class and which further arranges the mineral species into groups according to the more minute relations ….Read more

Crystal Structure of Solid Solutions using X-ray Spectrometer

“It would seem as if the methods used to date for the elucidation of this complex problem have yielded all they are capable of yielding and that further straining of these methods will only serve to confuse the issue, the point having been reached when this juggling, no matter how skilfully done, with allotropy, solid solutions, and strains is causing weariness without advancing the solution of the problem. The tendency of late has been to abandon the safer road of experimental facts and to enter the maze of excessive speculations, in which there is great danger of some becoming hopelessly lost. The conclusion seems warranted that new avenues of approach must be found if we are to obtain a correct answer to this apparent enigma.Solid Solution

With some degree of fitness we may say this of other problems. It seems likely that one of the new avenues of approach to many metallographic problems is the study of crystal structure, or more accurately, the atomic arrangement by means of the X-ray spectrometer.

The crystal structure of some materials has been carefully worked out by the mineralogist, but his methods are, in general, unsuited to ….Read more

Bulk Material Handling – Conveying & Silos

After beneficiation we now need to focus on the storage handling, and transport of the mined product which can be ore or coal to get it to the customer. As the products of mining are mostly grain able materials that are handled by disciplined known as bulk materials handling, which is the specialty of the discipline of mechanical engineering. In most cases, only a small proportion of the mined product can be sold to local customers which makes it necessary to use appropriate methods of handling and transportation to take the product to an export facility which maybe a long way away. Usually before the ore leave on a ship, it has been through multiple handling processes. After processing the ore is blended and stack on stock piles before it is dispatched of site using conveyors rail to rail transport. Belt conveyors are typical means to transport bulk materials over shorter distances or road rail transport are the preferred for long distances.2018 02 19 1515

Once the product arrives at the port facilities it is discharged and stacked on stockpiles gangue before it is finally loaded onto belt carriers to be exported ….Read more

Sluicing for Gold – Set up & Operation

And my pan now, what I’m going to do is, I’m going you down to that stinking river I was telling you about, it’s got a little bit of gold in there, don’t ask me where it’s at, because I’m not going to tell you. I’m going to show you the proper way to set up this sluice box, do some clean up and get some gold, so come on, let’s go.

Ok, so, what do we got. Alright now, if you going to be using a sluice box, what’s the first thing you got to do? That’s right! Grab a sluice box. This is a key 852- I love these things. Ah yea they’re a little big and they don’t fold down but I been using these type for years. Now I know they make all different type of ones that fold in and they’re collapsible. But I really like this one, it does a good job – it’s got good flow on it. So, next what you going to need? You going to need 5 gallon bucket. Now I see guys doing it without a 5 gallon bucket, but trust me, this makes a whole lot easier. Now, inside ….Read more

Mineralogy & Flotation: Floatability VS Selectivity Test Assessment

flotation_1Mineralogy is the driving force behind flotation performance. A flotation batch and rate test measures this as mass pull recovery and concentrate grade. The real data from a rate test can be processed to determine the flotation kinetics of metal, mineral and gangue. flotation_rate_determination_testWhat we cover here is what are kinetics and what do they mean. Special attention is paid to the definition of floatable gangue. How flotation kinetics are used to understand and optimized flotation performance is covered in the next series. Two other articles describe how a rate test is conducted and what concentrate collection times should be used. A laboratory batch test or measurements done a bank of pilots or production scale plant cells generates a recovery grade and concentrate mass profiled with time. determine_mineral_flotation_kinetic_speed_rateThese profiles describe the flotation response and performance of the ore under whatever conditions are in effect at the time. In 1961 Kelsall developed a first order two component equation to fit these profiles. Flotation performance is described in terms of Fast and Slow components; each has a fraction ….Read more

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