About David

Since 1993, when he obtained his Mining Engineering Degree from Queen’s University, David has acquired experience in operating roles including many years in post-commissioning operations troubleshooting. Mineral Processing and Metallurgy has become a core strength and passion for Mr. Michaud. Learn more at

Laws of Gravity Gold

Ten Laws of Gravity Gold Recovery



  1. Try to Evaluate the Economic Impact of Gravity Recovery
  2. Get a Statistically Significant Sample of the Ore to Evaluate Gravity Response on a Size-by-Size basis
  3. Design the Gold Recovery Circuit with a Good Understanding of Gold’s Behaviour in Grinding Circuits
  4. When GRG Recovery Is Not Indicated, Look at Other Options
  5. Design the Circuit for Ease of Operation and Mechanical Reliability Rather than Absolute Performance
  6. Improve Gold Room Performance
  7. Be Aware of Scale-up Problems
  8. Pay Attention to Screening
  9. “Overfeed” the Primary Unit
  10. Recycle
  1. Go for the BMW of Gravity Circuits: Nothing Can Be Too Good!
  2. Extract a Large Number of Samples, Look for a Few Gold Grains, Preferably Very Large Ones, and Use them to Justify Circuit Design
  3. Gold Gravity Is Just Like Any Other Gravity Recovery
  4. Try to Produce Bullion By Gravity at All Cost (literally…)
  5. Design the Circuit to Maximize the Recovery Effort… Most of the Time
  6. Focus Only on Primary Recovery
  7. Assume that Laboratory Recoveries Are Easily Reproduced at Plant Scale
  8. Don’t Pay Attention to Screening
  9. Maximize Primary Stage (Unit) Recovery
  10. Keep Operation “Simple” by Avoiding Recycling

The following statements

Mining Consultants List

mining consultants listMining consultants play a major role in the feasibility, planning, design and construction, operation and improvement of both small and large mines.  Consultants are experienced design engineers, mine designers, operating specialists or maintenance engineers who operate independently of operating mines.  They are available to work on:

  • mineral exploration projects, where start-up companies have not yet recruited their own staff;
  • mine and process plant conceptual design, engineering and construction where consultants’ greater experience can lead to significant cost savings prior to construction;
  • project start-up, where extra hands are needed to work the bugs out of the process;
  • mine and plant optimization, where a fresh set of experienced eyes can observe different dimensions of an operation and bring outside experience to solve problems;

The role of the consultant is changing with the major causes for change coming from:

  • major technical advances in communication, particularly the ability to transfer large amounts of information by telecommuting through e-mail and the internet,
  • the development of mine design packages and software systems that can be linked to databases accessed remotely by the mining operation and the consultant,
  • and the global unavailability of direct hire experienced technical staff (for operating companies and consultancies),
  • the

SAG Mill Manufacturer

Here is a list of the SAG Mill Manufacturers & Suppliers I know:sag_mill_suppliers

A highlight of SAG milling has been the collaboration between grinding mill manufacturers and mining companies. Experimental work on very large mills is difficult, expensive, and potentially catastrophic if it goes wrong, yet the work must be done if the mills are to be accepted for use. The results of the collaboration have been very successful, as can be seen by the large mills in use and the high treatment rates obtained at low cost per ton.sag-mill-manufacturer

There are a number of SAG mills in operation around the world with diameters reaching up to 40 ft. These operations continually invest in new technologies to improve their energy efficiency and capacity in their SAG circuit. Commercial SAG mill performance is determined by a large number of variables, both mine-site variables and mill variables. In many cases these variables dictate production capacity seemingly randomly. Therefore, a number of operating philosophies, each specific to a plant, have

Gyratory Screens

gyratory screen_motionGyratory Screen Separators impart a combined gyratory and vertical motion and arc used for fine-screening applications, wet or dry, down to 40 pm, including laboratory use. The basic components consist of a nest of sieves up to around 2.7 m in diameter supported on a table that is mounted on springs on a base. Suspended from beneath the table is a motor with double-shaft extensions, which drives eccentric weights and in doing so effects horizontal gyratory motion. Vertical motion is imparled by the bottom weights, which swing the mobile mass about its center of gravity, producing a circular tipping motion to the screen, the lop weights producing the horizontal gyratory motion. Ball trays and ultrasonic devices may be fitted below the screen surfaces to reduce blinding. Circular screens are often configured to produce multiple size fractions. These types of screens are typically used in low-capacity applications, one example being the dewatering of carbon in gold plants.

gyratory screen gyratory screens working principle

Electric Fluxer

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Industrial Box Furnaces

Our heavy-duty box furnaces are designed for an intensive and continuous use. Equipped with a ramp to set point digital indicating controller, our high temperature furnaces allow you to reach and accurately maintain the desired temperature. In order to minimize the heat up and cool down times, our furnaces are insulated with the best refractory bricks. The temperature control accuracy and the quality of the insulation of our furnaces enable you to achieve maximum performance and efficiency.

  • Heavy-Duty 2300°F Furnaces/1260°C
  • General Heat Treating
  • Annealing
  • HardeningThis is our high temperature industrial batch furnace. It looks like our tabletop furnaces for their interior design but offer higher continuous temperatures.

Let’s talk about one of our heavy-duty industrial box furnaces.  These furnaces are ruggedly constructed, heavy-duty, designed with high power ratings for production heat treating, processing heavy loads. A common Model is 54 inches high, 24 inches wide, 36 inches in length. We construct our models with angle iron frame, lined with a 10 and 12-gauge sheet metal. The front face plates are nice and thick. These are heavy-duty models.

The inside of the furnace is designed with heating elements on the side walls, door and backwall. On our even larger models,

Assay Furnace

As a dealer of a top Brand of manufacturers of ovens and furnaces, well known in the mining industry for the design and production of custom-built equipment. Knowledge of this industry has enabled us to design an improved assay furnace. Technologically advanced, this furnace has several unique features which facilitate its use and assure results of the highest quality.

Our BEST SELLING assay furnaces:

  • 1-year-warranty
  • 24 crucibles (30 gram crucibles)
  • Overall dimensions
    40” W x 40” D x 76” H
  • Working space
    14½” W x 22” D x 7½” H


Made of heavy gauge sheet metal, is specially formed to provide superior structural strength. The control panel is slightly recessed, providing protection for the electronic controls. All electric and electronic controls are grouped at the base of the furnace. These easy-to-read controls include:

  • PB-6 electronic analogue temperature control, calibrated at our plant;
  • PB-6 electronic over-temperature safety control, calibrated at our plant;
  • one ammeter (1 phase) or three ammeters (3 phase);
  • pilot lights and switches;
  • security compactors.


  • Refractory brick ensure excellent insulating properties, resulting in reduced heat-up time, increased temperature uniformity and lower production costs.
  • The materials used in the construction of the treating

List Factors Affecting Grinding Ball / Media Wear Rate

In the mineral processing Industry, there are different grinding environments in which grinding media are used. These include semi-autogenous (SAG) mills, rod mills, conventional ball mills, and tower mills. The different types of grinding media available for these grinding applications include heat treated and as rolled grinding rods, forged steel balls, cast steel balls, cast high chrome iron balls, and cast slugs (or cylpebs). Some media types are best suited for specific grinding applications. However, the areas of application often overlap, allowing a choice of more than one type of media for a given grinding application.

The consumption of grinding media in the mineral processing industry represents a substantial cost to the comminution process. Second to energy, grinding media is most often found to be the next highest consumable cost involved in mineral processing. To allow selection of the cost effective media, one must determine the specific wear mechanisms present in a given grinding application and decide which media system addresses these mechanisms most economically.

The effectiveness of grinding media in the mineral processing industry is evaluated in terms of wear resistance and grinding performance. Wear resistance is a function of alloy selection and processing, mill operation procedures, and the mill environment.

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