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2023 | NOTES FROM THE UNDERGROUND | All About The Mill Edition

Greetings from Black Hawk and Central City, Colorado, our mining and milling hometowns, out there on the edge of the Front Range,


My last Notes included a video of the Ball Mill start up. Pretty soon I’ll be sending you videos of the Rake Classifier in action as well as the Coarse Ore Bin installation. Pretty exciting stuff, although one responder wondered how this all comes together and how the mill works. After all, rock from the mine goes in one end and gold comes out the other – so allow me to put it together. Consider the following Process Flowsheet that diagrams the rocks’ transformational journey.




You may need to enlarge your screen as you move through the Process Flowsheet. Each important step is numbered, and those numbers indicate the following:

1.Coarse Ore Bin - this is where the trucks from the mine unload the tons of ore bearing rock

2.Vibratory Screen - this allows the small, gravel sized material to bypass the crusher, increasing the crushing efficiency

3.Jaw Crusher – as the fearsome name implies, this machine crushes the rock into gravel size between its manganese steel jaws.

4.Transfer Belt – this is a conveyor that moves the crushed rock below the screen and crusher to …

5.The Bucket Elevator is a vertical conveyor with buckets attached to the belt which lift the gravel sized pieces, offloading them high up into…

6.The Fine Ore Bin which is the highest point in the mill and storage spot for the rock before the…

7.Belt Feeder, which carries the rock into the ….

8.Ball Mill. This is an important stop. Whereas the Jaw Crusher crushed the rock, the Ball Mill grinds it, turning it from gravel to wet sand, after which it hits the…

9.Trash Screen, which does exactly what its name implies, removing any foreign objects (wood, plastic, etc.) before moving onto the….

10.Mineral Jig, a gravity separation device which segregates the heavier metallic bits from the lighter quartz and rock sending a largely metallic concentrate to the finishing table. Any oversized pieces are returned to the Rake Classifier.

11.After being screened into three sizes (coarse, medium and fine), the jig concentrate is run across the Finishing Table. The Finishing Table is the spot from which the larger visible gold is removed, and a series of heavy concentrates are created of each metallic sulfide mineral. Gold separated at this stage can be melted or “fused” into doré bars to be sold to third party refineries.

12.The Rake Classifier is a sizing device which sends the oversized material back up and into the Ball Mill for further grinding. Properly sized sand is then delivered to…

13.The Conditioner Tank where the pulp (slurry of wet sand) is treated with the non-toxic flotation chemicals which allow the metals to sink or swim depending on their surface electro-chemistry.

14.The Reagent Feeders introduce the non-toxic chemicals at the proper dosage to achieve the flotation separation.

15-17. These are the series of flotation machines (think big blenders) in which nontoxic chemicals stabilize air bubbles that pick up and float the gold (and silver) which prefer to be dry (in air) to the top of the tanks. The non-metallic particles prefer to be wet and sink. The gold is held in the froth on the surface of the tanks where a series of paddles continually scrape the rising froth off the tanks and into the ……

18. Concentrate Thickener which removes water from the slurry before it is pumped to the Concentrate Filter which removes as much remaining water as possible from the gold flotation concentrate so that it can be placed in sacks for transportation to third party smelters.

19 – 22 contain the steps necessary to dry the tailings. Tailings are the sands that are left over after the valuable minerals and metals have been removed. Because these rocks contain minor residual sulfide minerals they can’t simply be dumped on open ground. Rain and snow would eventually cause the rocks to create sulphuric acid which could allow small amounts of naturally occurring elements in the sand (cadmium, arsenic, mercury, etc.) to be released into the environment. As a result, we concentrate, dry, and treat the sand with cement and foaming agents before returning it as cemented rocks back to the mine from which they came, thereby preserving the environment and stabilizing ground that would otherwise by prone to sink holes. So – that’s the story. When completed and in full operation, the Golden Gilpin Mill will be working 24/7 cranking out as much gold as the Bates Hunter has to offer. In the late 1800’s and early 1900s there were mines and mills throughout Central City and Black Hawk. Black Hawk was known as “The City of Mills” with thirty of them going strong. Over the decades, thirty became zero. The day we start milling will be a day history is made.

Onward!

Commentaires


CAUTIONARY STATEMENT FOR PURPOSES OF THE SAFE HARBOR PROVISIONS OF THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995

 

This report may be deemed to contain “forward-looking” statements. We desire to take advantage of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995 and we are including this statement for the express purpose of availing ourselves of the protections of such safe harbor with respect to all of such forward-looking statements. Examples of forward-looking statements include, but are not limited to (i) projections of revenues, income or loss, earnings or loss per share, capital expenditures, growth prospects, dividends, capital structure and other financial items, (ii) statements of plans and objectives of ours or our management or Board of Directors, including the introduction of new products or services, or estimates or predictions of actions by customers, suppliers, competitors or regulating authorities, (iii) statements of future economic performance and (iv) statements of assumptions underlying other statements and statements about us or our business.

 

Our ability to predict projected results or to predict the effect of any legislation or other pending events on our operating results is inherently uncertain. Therefore, we wish to caution each reader of the report to carefully consider specific factors, including competition for products, services and technology; the uncertainty of developing or obtaining rights to new products, services or technologies that will be accepted by the market; the effects of government regulations and other factors discussed herein because such factors in some cases have affected; and in the future (together with other factors) could affect, our ability to achieve our projected results and may cause actual results to differ materially from those expressed herein.

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