[USCC] Using Compost for Mine Reclamation

[William (Bill) Carter]

Perry,
 
A few thoughts based on our ongoing research/demonstration work with a
rock quarry in north Texas:
There are at least 2 distinct uses for compost in rock/gravel quarry
reclamation. One is to support establishment of vegetation, which
subsequently provides erosion control. The other is immediate
stabilization. To accomplish the first, applying and incorporating
compost at the agronomic rate for available nutrients (not total
nutrients) is good, but it does not provide significant surface
stabilization before vegetation is established. A loose 1-2"
blanket/mulch layer of compost can provide immediate stabilization and
can prevent runoff from 1-2" of rain depending on intensity. TxDOT has
specified that compost used for this kind of erosion
control/stabilization be a 50:50 mixture of compost and wood chips,
which helps it resist wind erosion as well as absorbing and diffusing
the erosive force of rainfall and runoff. That is what we are testing on
an 8:1 slope. It is significantly out-performing hydromulch. I would not
count on it to provide reliable stabilization where concentrated flows
will occur without structural reinforcement such as netting. 
 
I have inserted a few specific responses in bold to your questions,
below.
 
     - Bill Carter
 
 
************
 
 
 
Bill Carter
Water Quality Monitoring & Assessment    MC 165
Texas Commission on Environmental Quality
P.O. Box 13087
Austin, TX  78711-3087
Phone:  512-239-6771
Fax:  512-239-4410
wcarter at tceq.state.tx.us

>>> plindquist at waukeshacounty.gov 12/11/2006 5:41 PM >>>
 
I am currently planning to use yard waste compost to reclaim a gravel
pit.  I was wondering if anyone else had done this before and had some
tips on things like:
 
1. Thickness/depth of compost to apply.  
Vegetation support: agronomic rate based on plant-available nutrients.
Erosion control: 1" on relatively level, less than 10:1 slopes; 1- 2"
on slopes between 10:1 and 3:1
2. Subsoil application recommendations (for root zone water holding).
3. Application process (for non-screened compost).
Vegetation support: shallow (3" to 4") incorporation e.g. discing
Erosion control: surface spreading as loose mulch layer
4. Possible mixing with submaterials (sand & gravel).
Shallow incorporation with soil/subsoil when intent is solely
vegetation support at agronomic rate
Leave as surface blanket for use in immediate stabilization
5. Seeding recommendations for Wisconsin climate (cover crop and
final).
6. Erosion control measures during stabilization (need for mulch,
erosion netting or polymer).
Mixing 50% with wood chips is generally good, and particularly
important on steeper slopes.
7. Application to the bottom of a storm water infiltration basin that
is seasonally wet. 
Should be fine.
8.  Any other recommendations.
Quarry operators often over-compact the reclaimed area, creating a
near-impervious surface which is difficult to vegetate. Request that a
surface layer be left uncompacted or that it be loosened by shallow
discing or similar treatment. Installing shallow swales on the contour
should help prevent rilling and erosion on long continuous slopes. Where
track equipment provides final contouring, ask that the tracking be done
to leave track marks perpendicular to the slope rather than running up
and down it, so as to leave mini-sediment barriers.