Cleveland-Cliffs – Tilden Mining Process Overview - video Dailymotion

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00:00Tilden Mining Process Overview Video. The Tilden mine is an open-pit iron ore mine. The active

00:15mining operation covers approximately 3,500 acres, excluding the tailings and water recirculation

00:21basins. Located on-site is a concentrator and pellet plant, where the iron is separated and

00:28concentrated and iron ore pellets are produced and shipped to customers. The basic surface

00:34mining process consists of the following steps. Exploration and engineering, drilling, blasting,

00:44loading, hauling, and dumping.

00:58Before mining occurs, the iron ore deposit is defined from exploration drill holes. These

01:04holes extend up to 2,000 feet below the surface and are spaced between 300 and 600 feet apart.

01:12From the drill core returned to the surface, geologists can map the deposit and assays are

01:18made to determine ore quality and to measure physical and metallurgical parameters. The

01:23resulting geological model allows a pit to be designed and mining scheduled to economically

01:29expose and extract the iron ore. The first step of the actual mining operation is to break the rock.

01:36Tilden uses electric-powered rotary blast hole drills to drill patterns of 200 to 300 holes at a time. The

01:44drill holes are 12 and 1 quarter inch diameter and 50 feet deep and are designed in a grid of

01:50approximately 30 feet by 35 feet. Pattern designs vary among the different material types at Tilden and

01:58are individually designed to cause the optimal fragmentation of the rock when blasted.

02:04The holes are then loaded with gassed emulsion bulk explosive. Electronic detonators are programmed to

02:11detonate each hole in precisely the right sequence, only milliseconds apart, but only one at a time.

02:17The blast is timed to maximize fragmentation of the rock while minimizing ground vibrations and airborne

02:24shock waves. Initiation of the blast is done wirelessly from a safe distance.

02:35Once the ground is broken, material can be loaded into trucks. Tilden utilizes multiple different types of

02:41equipment to dig the broken material and load trucks, the largest of which are electric rope

02:47shovels. The largest shovel at Tilden has a 60 cubic yard bucket which can load over 120 tons in a single

02:55pass, loading a 320 ton haul truck in three passes. This shovel is over 70 feet tall with the operator

03:03sitting 33 feet above the ground. Tilden also utilizes smaller electric rope shovels that have a bucket capacity

03:11of 45 cubic yards or 65 tons. If the broken material does not have economic value, it is considered

03:18waste rock and is hauled to a waste rock stockpile.

03:25When possible, old pits can be filled with rock as shown here. Otherwise, the rock is stockpiled above

03:32ground level in stockpile areas surrounding the open pit. Track dozers will maintain the dumping edges,

03:39allowing trucks to safely and efficiently dump their load and return to the loading site.

03:49Tilden also utilizes a fleet of large front-end loaders to load trucks at the mining sites.

03:56These wheel loaders have a bucket capacity of 28 cubic yards or approximately 50 tons.

04:03Because they are more mobile than the shovels, loaders can be moved around the pit day to day,

04:08mining ore more selectively, as required by ore blending plans.

04:14Tilden's primary hauling fleet consists of 320 ton haul trucks. These trucks have a payload capacity

04:21of 320 tons and are over 24 feet tall, 28 feet wide, and 50 feet long. They are powered by 3500 horsepower

04:32diesel engines driving electric wheel motors, allowing the trucks to travel 35 miles per hour on flat roads.

04:41However, when traveling loaded uphill at full power, these trucks can only achieve 7 miles per hour.

04:49Iron ore is hauled to the primary crusher, where it is reduced to a maximum size of 9 and 1 half inches in

04:56diameter in a gyratory crusher before being transported on conveyor belts to the concentrator.

05:03The actual crusher occupies five levels below the surface level dumping doors.

05:09The crushed ore is conveyed to a covered storage building, which is the end of Tilden's mining process.

05:15From there, processing of the crude ore is required to separate and concentrate iron,

05:21followed by pelletizing of concentrate. Pellets are shipped from Tilden to blast furnaces for production of steel.

Cleveland-Cliffs – Tilden Mining Process Overview

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