10.a2 Staff Report_2022 Tiller Mine AOP
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Memorandum
To: Scandia City Council Reference: Tiller Corporation— 2022 Mine AOP
Copies To: Ken Cammilleri, City
Administrator
Ryan Goodman, City Engineer
Kirsten Pauley, Sunde
Engineering
Project No.: 18407.000
Christina Morrison, Tiller
Corporation
From: Evan Monson, Planner Routing:
Date: March 10, 2022
SUBJECT: Tiller Corporation, Inc. – 2022 Annual Operating Permit Application for a
Mining and Processing Operation
MEETING DATE: March 15, 2022
LOCATION: 22303 Manning Trail
APPLICANT: Tiller Corporation (now owned by Martin Marietta Inc.)
REVIEW PERIOD: 60 day period ends March 28, 2022
ZONING: General Rural (GR), Aggregate Mining Overlay
ITEMS REVIEWED: Application, Plans and Related Submittals received January 28th; sub
consultant and agency comments, site visit findings
BRIEF DESCRIPTION OF THE REQUEST
Tiller Corporation has applied for its 2022 Annual Operating Permit (AOP) for their existing sand and
gravel mining operation located on Manning Avenue near 225th Street in Scandia. The site has been
actively mined since 1966, and currently operates under Conditional Use Permits (CUPs) granted by the
City on May 20, 2008. The Tiller mine site previously operated under a CUP issued by Washington
County when the County exercised land use authority within New Scandia Township. Permitted activities
included the mining and processing of aggregate, the production of hot-mix asphalt, and the recycling of
concrete and asphalt products.
The City’s Mining Ordinance specifies an AOP cycle that coincides with the active mining season.
Applications are due by January 31 each year, to enable permits to be approved before the start of the
mining season later in that year.
The applications for the Scandia Mine Site since 2010 have included both the Tiller site and the former
Dresel Mine site adjacent to them to the south. Tiller purchased the Dresel site in 2009 and operates both
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sites. The City issued a CUP for mining and processing at the Dresel site on May 20, 2008. As the owner
of both sites, Tiller is to comply with the conditions of both the Tiller and Dresel CUPs.
EVALUATION OF THE REQUEST
The Applicant is requesting an Annual Operating Permit (AOP) for a mining and processing operation.
The permit requirements are governed by Ordinance No. 103, Regulation of Mining and Related
Activities, which is Chapter 4 of the Development Code. The Ordinance requires review of the following
items for the AOP:
1. The operating conditions of the previous year and conditions required by the CUPs for the Tiller and
Dresel sites.
2. Proposed operating conditions and any variation from the previous year.
3. Results of the annual inspection by the City.
Conditional Use Permit Requirements
Tiller Mine Site
The City of Scandia approved a Conditional Use Permit (CUP) for sand and gravel mining and processing
at the Scandia Mine site for Tiller Corporation on May 20, 2008. The conditions included the items noted
on the table that follows. Tiller’s performance is indicated in the table on the following pages. There were
no issues identified in 2021 for the Tiller Mine site.
Condition Deadline
Specified
in CUP
Status Notes
1. Comply with CUP Ongoing + In process--monitored by City staff and
consultants
2. Comply with Rules
and Regulations
Ongoing + In process--monitored by City staff and
consultants.
4. Permits from
CMSCWD
None specified + CMSCWD Permit 08-003 for the Tiller mine
remains in effect.
5. Monitoring Wells July 20, 2008 + Three required monitoring wells were
installed in 2008. One well was taken out of
service and sealed in 2011 to accommodate
reclamation activities (MW-2). Monitoring
results for the two active wells in 2021 were
provided with the AOP application and
reviewed by LRE Water, the City’s
groundwater consultant.
6. Ground Water
Monitoring
July 20, 2008 + The Ground Water Monitoring Plan was
approved in the fall of 2008 and revised in
2013. The plan is on file with the City.
7. Excavation below
water table
May not begin
before August
20, 2008
* Excavation into the water table began in
2009. The CUP permits mining into
groundwater table to a depth of 50 feet.
Excavation into the groundwater table has
occurred as follows:
2013 – to a depth of 15 to 20 feet
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Condition Deadline
Specified
in CUP
Status Notes
2014 – no mining into groundwater table
2015 – no mining into groundwater table
2016 – to a depth of 15 to 20 feet
2017 – no mining into groundwater table
2018 – no mining into groundwater table
2019 – to a depth of 15 feet
2020 – to a depth of 40 feet
2021 – no mining into groundwater table
Water level data is collected on an ongoing
basis and submitted to the City. Water level
data was submitted with the AOP
application. The review from LRE Water,
water quality consultant for the City of
Scandia, is discussed in this report in the
Groundwater Monitoring section.
8. Production Well
Records
July 20, 2008 + Production well records are being kept by
Tiller and are available to the City. Water
pumped at the site in 2021 was 15,908,079
gallons. The current DNR Water
Appropriation Permit for the site allows up to
20 million gallons to be used each year: 18
million gallons per year for washing, and 2
million gallons per year for dust control.
Tiller has applied to the DNR for an increase
in their water appropriation permit to 30
million gallons a year.
9. Ground Water
Analysis - DRO
(Diesel Range
Organics) and
GRO
None specified + Groundwater samples were analyzed for
DRO. No gasoline is stored on site. If
gasoline storage is added, GRO will be
analyzed. Monitoring results were included
with the application and reviewed by LRE
Water. No DRO were detected in the
samples in 2021.
10. Map of Index Well
Sites
July 20, 2008 + Map was provided to the City on August 28,
2008.
11. Asphalt Plant
Setback from Lake
Ongoing + Setback has been maintained, as required
by the CUP.
12. Lake Depth Ongoing + Application indicates that the depth of
excavation will not exceed fifty (50) feet
below the water table, as per the CUP.
Excavation depth to date has been less than
50 feet into the groundwater table through
2021.
13. Truck Signage and
Roadway Cleaning
July 20, 2008 + Washington County has posted signs on
Lofton and Manning Avenues per their
County requirements. Tiller has posted
signs on 218th Street and at Lofton Avenue
to restrict trucks from using 228th Street per
City of Scandia requirements. During the
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Condition Deadline
Specified
in CUP
Status Notes
2020 construction season, a “No Engine
Breaking” sign is now being placed on
Manning Trail North near the entrance to the
site to address concerns of engine breaking
on the road. Signage was in place during
the City site visit in 2021.
14. Lofton/Highway 97
Intersection
July 20, 2008 + Tiller restricts importing add-rock from
Lofton Avenue during non-daylight hours per
the CUP requirements.
15. 228th Street signage July 20, 2008 + Signage is posted at the Lofton Avenue
North exit that restricts trucks from using
228th Street.
16-19. Updated
Reclamation Plan
July 20, 2008 + Included in application materials; discussed
below.
20. Letter of
Credit/Security
Due before
AOP approval
+ The financial guarantees are current.
21. AOP Application
Submittal
January 31,
annually
+ Application was submitted on January 28,
2022, and determined to be complete.
Dresel Mine Site
The City of Scandia approved a Conditional Use Permit for sand and gravel mining and processing for
Dresel Contracting, Inc. on May 20, 2008. Tiller Corporation now owns and operates this site, and
therefore must also comply with the conditions of the Dresel CUP. There were no issues identified in
2021 on the Dresel Mine site.
Condition Deadline
Specified
in CUP
Status Notes
1. Comply with CUP Ongoing + In process--monitored by City staff and
consultants.
3. Comply with rules
and regulations
Ongoing + In process--monitored by City staff and
consultants.
4. Permits from
CMSCWD
None specified * The CMSCWD Board renewed Permit 08-
003 for the Tiller permit in February 2019.
5. Installation of
Monitoring Wells
July 20, 2008 + Installed in May 2008. Groundwater Plan
was updated to reflect changes to
monitoring well MW-2 in 2013. The site
complied with the plan in 2021.
6. Revise Proposed
Conditions Plan Pit
Elevations
July 20, 2008 + The City previously approved a maximum
mining depth at 922 feet AMSL at the
Dresel site, ensuring three feet of
separation between the floor of the mine
and the water table surface during high
water table conditions, based on
monitoring results. LRE Water, water
quality consultant for the City of Scandia,
reviewed the submitted data and made
recommendations which are included in
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Condition Deadline
Specified
in CUP
Status Notes
this report under the Groundwater
Monitoring section.
7. Ground Water
Monitoring Plan
July 20, 2008 + Approved in October 2008 and on file at
the City.
8. Revise Site plan to
include Index Wells
July 20, 2008 + Provided to City on August 28, 2008.
9. Identify Bench Mark
Elevation
July 20, 2008 + Established at top of Well Casing MW-1.
10. Ground Water
Analysis - DRO and
GRO
None specified + Samples are analyzed for DRO when
mining activity is occurring. No gasoline is
stored on site. If gasoline storage is
added, GRO will be analyzed. No DRO or
other contaminants detected in 2021
monitoring at the Dresel site.
11. Signage on 218th
and Roadway
Cleaning
Ongoing + Signage was installed and meets the CUP
requirements; signage was in place during
2021 site visit.
12. Truck Cleaning Ongoing + Trucks must meet requirements for
cleaning, per CUP. No issues were
identified during 2021 site visit.
13. Delineate Northern
Wetland
None specified + Wetland report and delineation completed.
Buffer marked by September 15, 2008.
Complaint received regarding
encroachment into wetland in late 2014.
Mitigation and replacement plan were
completed and approved by TEP panel
and wetland credits successfully
withdrawn from the BWSR Wetland Bank
in 2016.
14-17. Updated
Reclamation Plan
July 20, 2008 + The Reclamation Plan was previously
revised as part of a combined Reclamation
Plan submitted for the Tiller Site.
18. Letter of
Credit/Security
Before AOP
approval
+ Financial guarantees are current.
21. AOP Application
Submittal
January 31,
annually
+ 2022 application was submitted on
January 28, 2022, and was determined to
be complete.
Proposed Operating Conditions, Changes from Previous Year, & Ordinance Requirements
Site Operations - Background Information
The Tiller mine site includes several parcels, as is indicated on the Site plan. Excavation activities in
2010-2011 removed material between the Tiller site and former Dresel Mine site, merging the two sites
into one. Tiller mined both sites in 2022. The mining operation includes removal of overburden;
excavation of sand and gravel; crushing, washing, screening, stockpiling of sand and gravel; recycling of
concrete and asphalt products; the production of hot-mix asphalt; and reclamation activities. The
overburden is removed from areas to be mined and stockpiled on the site for use in reclamation activities.
The operator brings portable crushing, washing, and screening plants to the site periodically and these
are used to process and stockpile materials. The operator produces and sells asphalt throughout the
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construction season and delivers add-rock materials to sites as needed to produce required mixes and
materials.
Mining into the groundwater table began at the site in 2009. This activity has been described in the
previous mining plans for this site and was evaluated in the Environmental Assessment Worksheets
completed for the Tiller site in 1987 and 1999. The CUP allows mining into the groundwater to a
maximum depth of 50 feet. Mining into the groundwater table occurred in 2013, 2016, and 2019 to a
depth of 15-20 feet, and in 2020 to a depth of 40 feet. Mining into the groundwater table did not occur in
2014, 2015, 2017, 2018, or 2021.
The asphalt plant at the site is equipped with a bag-house air pollutant collection device, and operates
under a Minnesota Pollution Control Agency (MPCA) Air Emissions Permit. Storage tanks as the site (for
fuel and asphalt cement) are regulated by the MPCA.
The main access routes to and from the site are Manning Avenue (County Road 15) and Lofton Avenue
(County Road 1). Both Manning and Lofton are paved. The haul road from Manning Avenue is paved
through the site to the hot-mix asphalt plant and loading area.
Annual Activity
The application submission included the data required by the ordinance regarding annual activity on the
site, as follows:
2019 2020 2021
Amount of material removed from the site (in
tons)
425,000 300,000 430,000
Amount of add-rock brought onto site (in tons) 60,500 61,000 77,000
Recycled asphalt and concrete brought to the
site
(in tons)
50,000 44,000 35,000
Average number of trips to and from the site
each day
(in trips/day)
214 184 225
This year’s application anticipates that mining and processing will continue at the site in 2022. The level
of activity will depend on market demand for the site products. The Site plan identifies the Potential
Mining Areas for 2022, which are within the approved mining limits. The areas are the same as what was
identified as potential mining areas for 2021. Potential areas for reclamation are also identified on the Site
plan; these are discussed later in this report.
Ground Water Monitoring
The approved Groundwater Monitoring Plan for the site is on file with the City. The City’s groundwater
consultant, LRE Water, reviews the groundwater monitoring results each year for the AOP and provides
comments to the City. LRE Water did not see any concerns with the 2022 application as it relates to
groundwater quality and quantity. Below are the 2022 Groundwater Monitoring Data Review Comments
from LRE Water:
• The 2021 groundwater monitoring was completed in accordance with the approved monitoring
plan;
• DRO was not detected above the method detection limit in any of the other wells for samples
collected in Sept 2021. These results and the other groundwater chemistry results indicate no
groundwater quality concerns;
• Groundwater flow direction across the site is generally to the north and consistent with previous
submittals; and,
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• From October 2020 through October 2021, groundwater levels across the site decreased an
average of approximately 1.5 feet and the pond by approximately to 2.5 feet. The most recent
levels measured on October 2021 are still 5 to 6 feet higher than the lowest levels measured in
2010. The decrease in water levels observed in 2021 is the result of local and regional changes
in precipitation, and unrelated to mining operations. This is shown by the annual precipitation data
that is plotted with water levels on the attached hydrograph. The water levels and precipitation
show similar trends over time.
LRE Water Recommendations:
• Continue the annual sampling for water quality parameters as outlined in the monitoring plan.
• Continue to map the area(s) of excavation into the water table.
• As recommended in LRE’s email to Ken Cammilleri, dated 1/18/22 on LRE’s Opinion on the
Tiller’s increased water appropriation, it is recommended that a short-term monitoring plan be
developed for measuring water levels in the production well and observation well PZ-3. This will
help confirm the aquifer recovers to pre-pumping water levels following period of pumping and
there is no long-term decline in water levels as a result of pumping during periods of high use.
• The 2022 AOP should indicate that Tiller (Martin Marietta) is proposing to increase its annual
water use permit from 20 MGY to 30 MGY.
Operating Conditions - Mining Ordinance Requirements, Section 7
1. Setbacks
The AOP application indicates that the minimum setbacks are maintained as follows:
• 50 feet from the adjoining property line
• 200 feet from any existing occupied structure not owned by operator or owner
• 100 feet from residential property subdivided into lots of 5 acres or less
• 100 feet from any road right-of-way
The setbacks meet the requirements of Ordinance No. 103. The City’s 2021 inspection indicated
that the setbacks were maintained and still meet City requirements.
2. Fencing
The application indicates that the majority of the site is fenced with 3-strand wire fencing, except
where prohibited due to topography, heavy vegetation and wetlands. There are locking metal
gates at both entrances. The fencing meets the intent of the City’s Ordinance. City staff reviewed
the fencing during the site visit 2021, and verified that it meets the requirements of the Ordinance
and CUP. Portions of fencing needing repair were identified during the site visit, and have since
been repaired.
3. Hours of Operation
The site is operated from 7 am to 7 pm Monday through Friday, except holidays. The applicant is
required to obtain the City’s permission for any extended hours in accordance with procedures
set in Ordinance No. 103, Section 7.1(3):
“(3) Hours of Operation. Those portions of the mining operation consisting of excavating,
stockpiling, processing, or hauling shall be conducted only between the hours of 7:00
a.m. and 7:00 p.m., Monday through Friday, unless other hours or days of operation are
specifically authorized by the City.”
Tiller requested, and the City approved, four extended hours requests in 2021. The requests were
for projects nearby in Chisago County, as well as for some nearby large state and county road
projects. In 2020, four requests were granted, while in 2019 there was one request granted. In
2018, the city granted extended hours on 14 occasions. Requests for extended hours vary from
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year to year, depending on projects and weather.
4. Screening
The mine is screened from surrounding areas by berms, wooded areas, and farm fields. A
number of trees have been planted over the years to augment the screening. Processing and
stockpiling operations are conducted in recessed portions of the site to minimize visibility.
5. Dust Control
Major haul roads are hard-surfaced or covered with asphalt millings as dust control measures.
The application indicated that Tiller used a water truck to control dust on unpaved portions of the
site, and calcium chloride was applied to minimize dust generated by trucking activity. These
actions were first implemented in 2019, and have been continued as needed since then. Tiller
plans to continue such practices as needed in 2022.
The CUP does not require additional dust control efforts.
6. Noise
The Applicant must comply with all Federal, State, and City noise standards.
7. Depth of Excavation
The CUP requires that the depth of excavation shall not exceed fifty feet below the water table
(865 feet above mean sea level) on the Scandia Mine site and may not be lower than 922 feet
above mean sea level (amsl) on the former Dresel Mine site. In 2020, excavation into the
groundwater table occurred in order to meet the gradation requirements of the final products. The
depth of excavation in 2020 was to an elevation of approximately 882 feet amsl. 2021 did not see
excavation into the groundwater table.
If excavation into the groundwater table occurs in 2022, it would occur within the 2022 Potential
Mining Area as depicted on their submitted site plan.
8. Site Clearance
Site clearing occurred along the east perimeter of the 2020 proposed mining area. There was no
clearing activity for 2021. If clearing activity does occur in 2022, it would occur within the 2022
Potential Mining Areas as depicted on their submitted Site plan.
9. Appearance/Condition
The City’s site inspection in 2021 confirmed that the site and facilities are maintained in a neat
condition.
10. Sanitary Facilities
The application indicates that the site is served by individual sanitary facilities that meet the
requirements of the City’s Ordinance and the Mine Safety and Health Administration. City staff
inspection confirmed that the City’s requirements were met in 2021.
11. Waste Disposal
The application indicates that waste generated by the operation is disposed of in accordance with
Federal, State and City requirements. The City’s site visit in 2021 confirmed that the Applicant is
meeting the requirements of the CUP.
12. Water Quality Monitoring Plan
The CUP required that Tiller Corporation complete a plan for groundwater monitoring within 60
days of approval of the 2008 CUP (July 20, 2008). The approved ground water monitoring plan
was completed and is on file at the City. Tiller submitted monitoring results for 2021 with its
application for the 2022 AOP. LRE Water reviewed the ground water monitoring activities and
found that no DRO (diesel range organics) were detected in the samples in 2021.
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13. Fuel and Chemical Storage
The application describes fuel and chemical storage at the site. The applicant notes that these
materials are stored in accord with Federal and State standards and County requirements. On-
site fuel storage consists of a 200-gallon above-ground storage tank which is located within a
steel secondary containment area and a 1,000-gallon above-ground double walled tank located
next to the standby electrical generator. When processing and/or reclamation crews are present,
an additional 1,000-gallon double walled tank is brought to the site and used to fuel the respective
equipment.
All asphalt cement storage tanks are above-ground. These tanks consist of two 40,000 gallon
tanks and two 32,000 gallon tanks. There is also a 20,000 gallon above-ground used oil storage
tank. The used oil is utilized as an alternative fuel supply for the asphalt plant. All tanks containing
asphalt cement and used oil are located within a concrete secondary containment area.
All tanks are registered with MPCA’s Storage Tank Program. MPCA Site ID 51999 is for the
asphalt plant and MPCA Site ID 55016 is for the sand and gravel operation. City staff reviewed
the facilities with Tiller staff at the 2021 site visit.
Small amounts of chemicals utilized by the QM Lab are regulated by Washington County under
United States Environmental Protection Agency (EPA) rules. EPA ID Number MND 981 953 417
has been issued for the site which is classified as a Very Small Quantity Generator.
14. Contingency Response Plan
The application indicates that the site operates under a Spill Prevention, Control and
Countermeasure Plan (SPCC) Plan that was submitted and is on file at the City. The applicant
notes that the mine operator will comply with other such reasonable requirements that the City
may find necessary to adopt for the protection of health, safety and welfare and/or prevention of
nuisance.
15. Processing
The CUP application describes the operation of permanent processing equipment on the site and
indicates that the equipment is operated in accordance with Federal, State and City air quality,
water quality and noise standards. The equipment is screened from view from other properties
and adjacent roads. The CUP requires that the asphalt plant and related structures be set back at
least 100 feet from the shore of the proposed lake on the site. The site visit in 2021 verified that
the processing facilities meet the setback requirements of the CUP, and no violations of permits
were reported in 2021.
16. Recycling
Recycling at the site is permitted by Ordinance 103. Asphalt production used approximately
35,000 tons of recycled asphalt products (RAP) in 2021. 45,000 tons of RAP was brought in to
the site in 2021; at year-end there was 59,000 tons of RAP on the site. Processed RAP is used in
asphalt production and recycled concrete is sold in various aggregate products.
A Solid Waste Storage Facility license that authorizes the storage of unprocessed concrete,
concrete products and brick and a Recycling Facility license that authorizes the storage and
processing of recycled asphalt products are issued to Tiller by Washington County. General and
Specific Conditions are established for each license and are reviewed on an annual basis and
may include an annual inspection completed by the County.
17. Trucking Operations
The application indicates that the site has access to County Road 15 (Manning Trail N.), County
Road 91 (Lofton Avenue N.) and 218th Street North. These are hard-surfaced roads. The
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operator reported that the average number of trucks travelling to and from the site per day in
2021 was approximately 225 trucks per day.
The proposed conditions for the 2022 AOP include the same as those included in previous
AOP’s, which require that Tiller inform all contractors about the following requirements related to
trucking operations, and monitor compliance with the requirements by all of its contractors:
• Engine braking is prohibited in Scandia
• Lofton Avenue is restricted to daytime use only
• Loads are required to be covered
In 2020, a “No Engine Breaking” sign was installed on the northbound lane of Manning Trail North
near the entrance to the site to alert truck drivers entering the site. This sign will again be up
during construction season, and removed during the offseason.
18. Asphalt Plant
The site operates a permanent hot-mix asphalt plant that was in operation at the time the C ity
adopted its mining ordinance. The plant operates under an air quality permit issued by the MPCA
and must meet federal, state and city air, water and noise standards. The City received no
complaints regarding the operation of the asphalt plant in 2021.
Reclamation Plan - Mining Ordinance Requirements, Section 8
Section 8.2 of Ordinance 103 requires the “restoration shall proceed concurrently and proportional to
actual mining operations and will be subject to review and approval at each annual inspection and at the
end of the permit period.” This section is included in the ordinance to ensure that large areas of the site
are not left in an un-reclaimed state, encouraging erosion, dust, and weed establishment. The mining
operation is making an ongoing investment in reclamation, to avoid potential problems that may occur at
the end of the mining operation if a large investment is needed in reclamation, and the applicant’s
resources are limited at that point, or the applicant abandons the site.
Section 8.4 of the City’s Mining ordinance requires the following for reclamation areas:
• All banks must be graded or backfilled
• Graded or backfilled areas shall be surfaced with soil of a quality at least equal to the topsoil of
areas immediately surrounding, to a depth at least four inches
• The topsoil shall be planted with trees, shrubs, legumes or grasses
• Slopes shall not be steeper than 4:1
Reclamation activities in 2021 included seeding and mulching an area south of the Scandia Mine/Dresel
Mine common mining border. Placement of overburden and suitable fill material along the slopes of the
mining area, north of the Scandia Mine/Dresel Mine common mining border is ongoing. The completed
and ongoing reclamation areas are indicated on Figure 2 of the submitted Site plan.
Ongoing reclamation activities are anticipated north and south of the Scandia Mine/Dresel Mine common
mining border and primarily along the east half of the mining area, during 2022. These areas are shown
on Figure 2 of the Site plan as ‘2022 Potential Reclamation Activity’. Some of the areas shown as
potential reclamation may also see active mining during 2022. Once mining is complete, reclamation may
advance into these areas during 2022. The reclamation completed meets the requirement of the CUP.
Watershed District Comments
The current CMSCWD permit runs until completion of mine activities, with some exceptions as identified
in the permit. The permit requires the applicant to complete the following activities on an annual basis:
1. Provide a copy of the annual AOP performance submittals for the City of Scandia, to the
watershed for review.
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2. Coordinate a site inspection by the CMSCWD Administrator
3. Reimburse CMSCWD for all expenses associated with implementation of the permit.
Site Inspection
City staff completed a site visit to the Tiller Corporation Scandia Mining Operation on November 12, 2021,
including documenting conditions on the site. The site visit reviewed activities and site conditions based
on the CUP and 2021 AOP, and discussed impacts from the pandemic and expected activity in 2021.
Staff identified areas of existing perimeter fencing in need of repairs or remounting of signs hanging
sideways, along with some areas needing signage upgrades. Apart from this, the inspection showed
nothing of concern.
ACTION REQUESTED
The City Council can:
1. Approve the AOP, with or without conditions
2. Deny the application, if it is found that the request is not consistent with the Comprehensive Plan,
CUP, AOP Criteria, and Mining Ordinance, and is not in the best interest of the community
3. Table the request if the Council needs additional information to make its decision.
RECOMMENDATION
City staff recommends approval of the Tiller Corporation 20 22 AOP for sand and gravel mining and
related processing at the Scandia Mine, 22303 Manning Avenue North, with the following conditions:
1. The applicant shall comply with the conditions of the Conditional Use Permit for sand and gravel mining
and processing at the Scandia Mine site approved on May 20, 2008.
2. The applicant shall comply with site operation hours of 7 a.m. to 7 p.m. Monday through Friday,
except holidays, unless the applicant requests and receives the City’s permission for extended hours
in accordance with procedures set forth in Ordinance No. 103.
3. The applicant shall continue to observe groundwater levels during the year. If levels continue to rise,
there is the potential for the water table surface to be above the depth of the excavation and outside
of the limits of the proposed lake. If this occurs, maps submitted for the 2023 AOP shall identify the
general areas where excavation depth is below the water table.
4. The applicant shall provide the approximate depth of the excavation below the water table in future
annual reports to confirm the excavation did not go below the 865.87 feet amsl threshold.
5. The applicant shall continue to provide the production well records for the site to the City so the
pumping records can be compared to past and future groundwater level trends at the site. The
applicant should measure the water level in the production well under non-pumping conditions during
monitoring periods.
a. Per the recommendation of LRE Water, as a result of the requested increase in water
appropriation from 20 MGY to 30 MGY, a short-term monitoring plan be developed for
measuring water levels in the production well and observation well PZ -3. This will help
confirm the aquifer recovers to pre-pumping water levels following period of pumping and
there is no long-term decline in water levels as a result of pumping during periods of high
use.
6. Requests for operating hours or haul routes outside those specified in the Conditional Use Permit shall
be accompanied by a proposed truck haul route for approval by staff.
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7. The applicant shall inform its contractors about the following requirements related to trucking
operations, and monitor compliance with the requirements by all of its contractors:
• Engine braking is prohibited in Scandia
• Lofton Avenue is restricted to daytime use only
• Haul loads are required to be covered
8. The applicant shall regularly monitor the entrances and exits to the site, and work with their hauling
contractors and truck drivers to maintain compliance with traffic laws.
9. The Reclamation activities shall meet the requirements of the Conditional Use Permit, including soil
and planting requirements.
10. If the applicant has knowledge that a crash or traffic violation occurs involving a truck hauling for
Tiller, Tiller shall contact the City to report the incident immediately. The applicant shall report actions
it will take to respond to the incident.
11. The applicant shall pay all fees and escrows associated with this application.
12. This Annual Operating Permit shall expire on March 31, 2023.