1.       Diversion Channel

Excavation of the half mile channel is near completion.  The south end (entrance) of the channel is complete; a rock layer covers the base and extends approximately 4- feet along the side slopes and the 450-foot length has been re-vegetated. 

The next 300-foot section enters into the first tailings section of channel.  The weak tailings material would not support a slope; therefore, the channel was over-dug and refilled with subsurface soils recycled from throughout the Site.  This portion of the channel is currently being used as an access point to the south end.  This allows for time for the soil to settle and compress and also allows for tailings to drain. 

The next 900-foot section is at grade, re-vegetated and holding groundwater that is used throughout the Site for various purposes.   This section is being used to quarry granite and shale; this rock is then used to line the diversion channel and complete the shear key. 

The following 500-foot section is again in tailings.  It has been over-dug and covered with a six to eight inch buffer of wood ash.  This section is currently being prepped for liner and rock installation. 

The final 500 feet was again blasted through the mountainside.  It is the deepest and steepest portion of the channel.  It has sheer sides and depths of approximately 50-feet in sections. 

The channel continues to be dammed until the entire length is buffered, limed, rocked and re-vegetated.

2.       Site Ponds

There were four ponds holding water on the Site.  Ponds 1 and 4—the two northernmost water bodies—have been completely filled.  Tailings were used as a base fill.  It was then covered with a 3 to 12 inch lime buffer.  The depth of the lime buffer varied depending on the reactivity of the tailings.  Approximately two feet of subsoil was then added, followed by a thin layer of topsoil.  The area was then re-vegetated.  Pond 2—by far the largest—is still being filled with tailings.  Pond 3 has been filled and covered with lime.  It will be capped and re-seeded after culverts are laid.

3.        Tailings Dam

A.      Sediment Pond

The sediment pond is still functioning as engineered.  Temporary piping still exists in the riser and outlet pipe.

B.       Starter Dam

Ditches were dug in the starter dam for two purposes: to allow the dam to drain freely and to confirm the composition of the starter dam as described in the Tailings Dam Inspection Report.   The anticipated colluvium layer was not found; instead, the dam appears to have been constructed with mostly tailings and a thin clay cap. 

C.      Shear Key

The shear key is approximately 35% completed.  The key rises to 30-feet at its apex and will stretch the length of the starter dam when complete.  It is placed at the toe of the starter dam and is being constructed in three sections: the first made of granite, rising 30-feet high and 30-feet wide; the second is a sand filter with the same height and two feet thick; the third section is constructed exactly as the first.  The largest pieces of granite obtained during blasting operations are being used as the base of the key.  The base is anchored into native rock and stable soil for added strength.

D.       Main Tailings Impoundment

The lower portion of the road leading to the impoundment has been re-routed so that re-sloping of the dam face may begin.  Currently, the impoundment is being used as a staging area for all material generated during the project. 

4.        Other/Miscellaneous

Constant rainfall has greatly hampered Site activities, increasing site costs and extending the project schedule.  This—along with additional site quarrying for rock—is anticipated to increase the Site ceiling.  An additional 3,300 cubic yards of rock may be needed to complete the diversion channel per engineering specifications.

Quarrying rock from the Site has resulted in great cost savings compared to purchasing and transporting material from a vendor.

The sand filter in the shear key is being constructed with gravel and clean, uniform, evenly-sized specialty sand.  Special care has been taken not to contaminate any portion of the key with any other material than granite and sand.  Introduction of material such as tailings and clay would clog the structure, thus reducing its effectiveness as a filter. 

A railing will be built along the final 500 feet of the diversion channel as a safety measure.

In an effort to reduce the carbon footprint of the Ore Knob Mine Site, all paper and plastics are being recycled and no construction waste is being generated on-site.  All soils, rock and water is recycled for use onsite—thus eliminating transportation and disposal costs. 

Constant rainfall has greatly hampered Site activities, increasing site costs and extending the project schedule.  This—along with additional site quarrying for rock—is anticipated to increase the Site ceiling.  An additional 3,300 cubic yards of rock may be needed to complete the diversion channel per engineering specifications.

Quarrying rock from the Site has resulted in great cost savings compared to purchasing and transporting material from a vendor.

The sand filter in the shear key is being constructed with gravel and clean, uniform, evenly-sized specialty sand.  Special care has been taken not to contaminate any portion of the key with any other material than granite and sand.  Introduction of material such as tailings and clay would clog the structure, thus reducing its effectiveness as a filter. 

A railing will be built along the final 500 feet of the diversion channel as a safety measure.

In an effort to reduce the carbon footprint of the Ore Knob Mine Site, all paper and plastics are being recycled and no construction waste is being generated on-site.  All soils, rock and water is recycled for use onsite—thus eliminating transportation and disposal costs.