Comment Location (Chapter/Section/Page/Line)

Jurisdiction / Special Expertise / Citation

Comment / Rationale / Basis

General Comment

Considering Cumulative Effects Under the National Environmental Policy Act, * Council on Environmental Quality, January 1997, Public Law 106-538, An Act To establish the Las Cienegas National Conservation Area in the State of Arizona.

The cumulative effects of similar past, existing, and reasonably foreseeable activities affecting the resources affected by the Rosemont Project have not been adequately addressed and disclosed. Considering Cumulative Effects Under the National Environmental Policy Act , Council on Environmental Quality, January 1997 [https://ceq.hss.doe.gov/publications/cumulative_effects.html], provides a framework for scoping, describing, and analyzing cumulative effects in NEPA documents.

Groundwater Quantity, Page 1, line 16

�Davidson Canyon/Cienega Basin� should be replaced with �Davidson Canyon�. The current language suggests that fracture flow is the primary flow mechanism in the Cienega Basin.

Groundwater Quantity, Page 1, line 20

.

The word �could� should be replaced with �will�, since we know that impacts to wells, springs, streams, and riparian areas and seeps springs, seeps, will occur although we may not know exactly by how much.

Groundwater Quantity, Page 1, line 21

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�impacts�� [Add:] � to both the Santa Cruz and Cienega Creek watersheds� to the end of the sentence.

Groundwater Quantity, Page 1, lines 37 and 39

The word �may� should be replaced with �will�, since these types of impacts will occur although we may not know exactly by how much. This comment applies to many other places throughout the DEIS where analysis have already estimated a range of impacts that are predicted/expected to occur from a specific activity.

Groundwater Quantity, Page 5, line 38

The 10-foot drawdown threshold of concern is fine to use, but do not forget that the model's level of accuracy can err in both directions. The model could underestimate effects just as easily as it could overestimate them. Therefore the 0' (zero) line is more appropriate for any graphic displays of the extent of the cone of depression, since it represents the he midrange of any possible error. Showing only the 10-foot line only shows the underestimated extent, and is another way of arbitrarily �biasing or under-reporting� the actual results of analysis. This comment remains unaddressed from the previous review.

Groundwater Quantity, Page 12, lines 35 - 37

With a growing number of wells, groundwater pumpage in the Sonoita area has been an issue of much discussion. It should NOT be assumed that pumpage is � negligible �. How was the 400 � 500 AFA estimated? This estimate is not negligible when compared to small and sensitive stream flows within the Las Cienegas National Conservation Area (LCNCA). The cumulative effects of pumping 350 � 400 wells and the estimated reductions of stream flow are foreseeable and significant in the Cienega creek Basin that will eventually also have to extend affects to Davidson Canyon to some degree. This comment remains unaddressed from the previous review.

Groundwater Quantity, Page 12, lines 38 � 44 and Page 13, lines 1 -10

Modeling this fractured rock aquifer with known significant geologic faults as a homogenous porous media with a finite difference model may not be the most appropriate approach. Model results should be used very conservatively. This comment remains unaddressed from the previous review, but BLM is not asking for any re-modeling. Language accurately describing the limitations of this modeling assumption needs to be added.

Groundwater Quantity, Page 15, line 39

The water balance in Tetra Tech's calibration shows that 60% of the water budget is completely unrestrained flow in and out of the external model boundaries; and it appears (per contours) that the external inflow is modeled primarily as inflow from the Whetstone Mountains (we know that the largest recharge basin is in the Santa Rita Mts.), which should have been constrained with a recharge estimate for the area between the model boundary and the Cienega basin boundary. Apparently the model has a large flow through the Cienega Basin which could limit the modeled extent of project impacts to the southeast into the Cienega Basin . The high inflow from the boundaries may control the ET and streamflow discharges. This comment remains unaddressed from the previous review, but BLM is not asking for any re-modeling. Language describing the limitations of this model's boundary conditions needs to be added to the DEIS.

Groundwater Quantity, Page 15, line 41

With a growing number of wells, groundwater pumpage in the Sonoita area has been an issue of much discussion. It should NOT be assumed that pumpage is � negligible �. How was the 400 � 500 AFA estimated? This estimate is not negligible when compared to small and sensitive stream flows within the Las Cienegas National Conservation Area (LCNCA). An inventory of all wells with the necessary information to more accurately analyze impacts to local wells is not � prohibitively costly and time consuming �; and it should be conducted to provide a much higher level of confidence in the model predictions. Much/most of the necessary information is available with the ADWR records. This comment remains unaddressed from the previous review.

Our preliminary research shows that as of 2009 there are a total of 1,886 exempt wells in the basin. This represents an increase of about 49% since 1990 when there were 1,263, and a 29% increase between 1990 and 2000 with 366 new wells registered in that period. Furthermore, there is much State land available in the Sonoita area for continued expansion of developments and new wells.

Groundwater Quantity, Page 16, line 1

The horizontal flow barrier (HFB) simulating an intrusive quartz-porphyry dike damming off groundwater flows from upper Davidson Canyon to lower Davidson Canyon is not supported by any data nor by any on-the-ground observations such as changes in vegetation, or higher groundwater levels on the upstream face of subject geologic feature. Without any supporting evidence of its hydrogeologic effects or its existence, the HFB should be eliminated from the model.

Groundwater Quantity, Page 16, lines 3 and 4

Modeling this fractured rock aquifer with known significant geologic faults as a homogenous porous media with a finite difference model may not be the most appropriate approach. Model results should be used very conservatively. The behavior of this fractured rock hydrogeologic system may not be accurately characterized, even with the additional 30 wells and 17 piezometers. Limestone solution piping/caverning could occur below the pit in this highly fractured rock geologic setting, but there is no way this would ever be predicted using a finite difference model with a homogenous porous media. Pump testing only five (5) wells may not be enough to accurately calibrate the finite difference transient model especially when using a homogenous porous media structure in this fractured rock geology. Caution in use of model predictions near the pit, is especially warranted for evaluating impacts to springs on the west side of the pit and topographic divide.

Groundwater Quantity, Page 16, lines 42 and 43 and page 17, line 1

Calibration difficulties are further evidence of the uncertainties presented by using a homogenous media model to model a fractured rock system.

Groundwater Quantity, Page 17, lines 1-3

This statement should include streams, springs, seeps and cienegas (not just wells).

Groundwater Quantity, Page 17, line 9 and lines 33-38

The use of constant head boundaries artificially provides unlimited external groundwater inflow from the Whetstone Mountains even though the largest recharge basin is in the Santa Rita Mountains, which should have been constrained with a recharge estimate for the area between the model boundary and the Cienega basin boundary. Apparently the Tetra Tech model simulates a large flow through Cienega Creek Basin which could limit the modeled extent of project impacts to the southeast into the Cienega Basin . The high inflow from the boundaries may also control the ET and stream flow discharges. Since balance of the model relied on adjustments of groundwater flux at its boundary conditions, what are the implications to the model's predictive accuracy? BLM is not asking for any re-modeling. Language clearly describing the limitations of this model's boundary conditions needs to be added to the DEIS.

Groundwater Quantity, Page 18, lines 16-22

The horizontal flow barrier (HFB) simulating an intrusive quartz-porphyry dike damming off groundwater flows from upper Davidson Canyon to lower Davidson Canyon is not supported by any data nor by any on-the-ground observations such as changes in vegetation, or higher groundwater levels on the upstream face of subject geologic feature. Without any supporting evidence of its hydrogeologic effects or its existence, the HFB should be eliminated from the model.

Groundwater Quantity, Page 19, lines 5 and 27

Full peer review of the Myers model should be completed. Objective statistical documentation of the calibration analysis must be provided for peer review. This comment remains unaddressed from the previous review.

Groundwater Quantity, Page 21, line 17 and lines 25-27

The fact that ADWR cannot deny this permit to mining operations needs to be clearly stated.

Groundwater Quantity, Page 27, lines 28-30 and Page 28, Figure 3.3a

Indicate incremental additional land subsidence is expected on an annual basis due in part to groundwater withdrawals associated with mine supply water. Because the model is locally modified, local impacts may not be accurately represented if it is still based on a regional calibration. Accurate determination of predicted impacts must be based on calibrated results; not just �relative� changes.

Groundwater Quantity, Pages 52-54, Tables 3.7 - 3.11

All the entries showing � None � in Tables 3.7 through 3.11 should be changed to �< 5ft� as per small font footnote, these � indicate that drawdown was less than 5-feet �, which would be significant and certainly much more than it would take to totally deplete baseflows in the perennial reaches of Cienega Creek and Davidson Canyon. Drawdowns were predicted to diminish flows in Cienega Creek by at least 0.09 CFS, or about 1% - 3%. These estimated reductions cannot be considered � minor �, especially if drought conditions persist. Such reductions can be expected to affect existing uses and riparian/aquatic habitats. Additionally, Montgomery and Myers should also analyze the 50-year period, for Table 3.9. At least one more stream flow monitoring point is needed along Cienega Creek between Gardner Canyon and the USGS gage.

This comment remains unaddressed from the previous review. However, Upper Empire Gulch Springs was added to these tables in response to previous review comments.

Groundwater Quantity, Page 54, line 18

Fractured bedrock comprises only the mountainous portion of the regional aquifer. The major streams in the basin are located in the inner valley which is comprised of regional basin fill. Such streams usually also have much smaller groundwater flows in their underlying shallow floodplain alluvial sediment substrates.

Groundwater Quantity, Page 55, line 20

Fractured bedrock comprises only the mountainous portion of the regional aquifer. The major portion of the regional aquifer, located in the inner valley, is comprised of regional basin fill.

Groundwater Quantity, Page 56, lines 1-9

A full description is needed of the criteria and methodologies used by Tetra Tech to draw several conclusions about the source of perennial water to Reach 2 Spring and Escondido Spring. Baseflows in streams, as well as perennial flows in most springs, are supported by regional groundwater levels. Any contributions from shallow alluvial sediments are secondary and superimposed on top of regional groundwater levels and would quickly subside to underflows if the regional groundwater levels diminish significantly. The source of perennial flow in Davidson Canyon is more likely to be a combination of storage in the limited sediments and banks, and groundwater contributions from the regional aquifer � not just bank/sediment storage. This flow persists through long periods of many dry years and is more than could be supported by bank/sediment storage alone. The regional aquifer is likely to be the more significant source for perennial flows in Davidson Canyon. A perennial stream length reduction of at least 41% as modeled represents a major impact to this stream and all of its related riverine amenities.

Groundwater Quantity, Page 57, line 14

The regional aquifer includes inner valley regional basin fill, not just fractured bedrock.

Groundwater Quantity, Page 57, lines 31-33

Riparian trees can begin to suffer right away. Water-level declines in stream channel reaches with riparian vegetation could result in reductions in plant health, density, and distribution. The regional water table would NOT have to be lowered beyond the root depths to cause canopy dieback in vegetation that is dependent on groundwater.� Riparian vegetation will begin to suffer as soon as groundwater levels begin to decline. Vegetation will definitely die when levels fall below the root zones, but impacts including death can and usually do occur commensurate to declines. Stressed trees are much more vulnerable to insect infestations, and disease as water levels decline. Recruitment of young tress is also affected early in the diminishment of baseflows and groundwater levels. By then all lesser (shallower-rooted) riparian vegetation would be gone. This comment remains unaddressed from the previous review.

The effects on riparian vegetation in Empire Gulch must also be respectively analyzed.

Groundwater Quantity, Page 59, lines 1-12

This partially address a previous comment by analyzing the effect of mountain front recharge, but needs to clearly say the effect is a negative impact and needs to explain how the mountain front recharge reduction was calculated.

Groundwater Quantity, Page 66, lines 29-31

The 5-8 feet/year of increased drawdown due to mine water supply extractions is significant.

Groundwater Quantity, Page 66, lines 37 and 38

Additional incremental extractions of groundwater normally would be expected to cause commensurate incremental additional land subsidence. How was this contrary conclusion reached? What criteria and methods were used in deriving the estimates?

Groundwater Quantity, Page 67, lines 19 � 21; Page 68, lines 6 � 8; 16 � 18; and 31- 33

The proposed locations for recharge are too far down-gradient to provide any actual offset to the drawdown from the proposed mine supply pumpage. The �off-set� would only be theoretical to the over-all water budget of the Tucson AMA as a whole, but none (of no benefit) to the impacted area. This comment remains unaddressed from the previous review.

Groundwater Quality, Page 1, lines 7 � 9

The lesser quality of CAP water for recharge should be considered in evaluating the potential impacts to the local aquifer in the Upper Santa Cruz Sub-basin. The potential for lower quality water with increased pumping depth should also be addressed. The mine pumping in the Upper Santa Cruz Sub-Basin should be included in the analysis of groundwater quality. This comment remains unaddressed from the previous review.

Groundwater Quality, Page 4, line 29: Table 3.1

The table should be expanded to include in the Issue Category, any potential impacts from mine supply extractions in the Upper Santa Cruz Sub-Basin, as well as potential impacts to downstream habitats, environs, and populated communities in the Cienega-Davidson Basin. This comment remains unaddressed from the previous review.

Groundwater Quality, Page 12, lines 16 - 24

A detailed fate and transport modeling of these scenarios should be conducted. Groundwater flow directions under the heap leach facility are difficult to accurately predict in a fractured rock aquifer, especially when modeled as a homogenous porous media. This comment remains unaddressed from the previous review.

Groundwater Quality, Page 15, lines 4 � 8

The pit's bottom and sidewalls will be fully exposed to air and water (rapid weathering), and located in a fractured rock formation. All of the constituents identified as present in leaching from source rocks in the geochemical modeling report have not been analyzed and reported in the supporting geochemical modeling report, for a complete evaluation of possible impacts to groundwater quality. Additionally, the behavior of this fractured rock hydrogeologic system may not be accurately characterized.

Groundwater Quality, Page 17, line 4

Ambiguous statement. Can this be more clearly stated?

Surface Water Quantity, Page 1, lines 15 - 18

Expected reductions in ephemeral flows to Cienega Creek should not be considered negligible just because they would be less impacted than flows to Davidson Canyon. The relative differences between the portions affected in each watershed should be evaluated to fully address the significance within each watershed. Other factors, such as location relative to higher elevations, wind and storm track directions, land use, vegetative type and cover density, soils and topography must to be evaluated.

Surface Water Quantity, Page 4, Table 3.1

Another criteria that should be added for evaluating when the effects on water resources should be considered to be significant is: the cumulative effect of numerous �minor� impacts. Decreases in vegetative cover and soil loss can affect watershed function, with resultant hydrograph alterations, (usually unfavorable peak flow increases). This comment remains unaddressed from the previous review.

Surface Water Quantity, Page 10, lines 24 and 25

Cienega Creek has a significant perennial reach within the LCNCA. Downstream of the LCNCA, Davidson Canyon also has a significant perennial reach. This comment remains unaddressed from the previous review.

Surface Water Quantity, Page 12, lines 3 - 5

Cienega Creek has a significant perennial reach within the LCNCA. Downstream of the LCNCA, Davidson Canyon also has a significant perennial reach, so the words �and perennial' should be added at the end of line 4. This comment remains unaddressed from the previous review.

Surface Water Quantity, Page 12, line 20

As mentioned above Cienega Creek has a significant perennial reach within the LCNCA above the USGS gage. At least one more stream flow monitoring point is needed upstream within the LCNCA along Cienega Creek between Gardner Canyon and the existing aforementioned USGS gage. This comment remains unaddressed from the previous review.

Surface Water Quality, Page 1, lines 22 � 24

Issue 3E Factors for alternative comparison should include �Changes in downstream riparian vegetation in response to changes in surface water quality�. This comment remains unaddressed from the previous review.

Surface Water Quality, Page 3, lines 37 � 44 and page 4, lines 1 - 4

Off-site construction of above-ground power lines, water supply lines, and access roads should be analyzed, as these activities most certainly can affect surface water quality. At a minimum, Pima County drainage standards should apply. Stream course or drainage pattern alterations should not occur. All streams should continue to flow into their natural courses. No �gathering� or �consolidating� of several small streams into larger crossings and larger drainage structures should occur. Additionally, all disturbed areas should be hydroseeded with native grasses and completely stabilized with appropriate storm water BMP's, as part of a complete Storm Water Pollution Prevention Plan (SWPPP) that should be prepared. Effective detention upstream of culverts can be designed to have positive effects of reducing peak flows and extending flow durations, which can promote better flow regimes, increase recharge, and generally improve habitats. Proper erosion control/energy dissipation measures should be designed at all culvert watercourse crossings. This comment remains unaddressed from the previous review.

Surface Water Quality, Page 4, line 2

All of the negative values in Table 3.1 represent sediment-deficient flows (�hungry water�), which can be expected to cause downstream erosion. This comment remains unaddressed from the previous review.

Surface Water Quality, Page 10, lines 11 - 16

How were sediment yields calculated? This comment remains unaddressed from the previous review.

Surface Water Quality, Page 14, lines 8 - 19

Sediment yield impacts on the Santa Cruz side also need to be analyzed. Off-site construction of above-ground power lines, water supply lines, and access roads should be analyzed, as these activities most certainly can affect surface water quality. This comment remains unaddressed from the previous review.

Surface Water Quality, Page 15, lines 3 - 4

Landforming of tailings and waste rock should be considered as a viable alternative to benches/buttresses, which can be expected to greatly reduce the potential for on-site erosion and increased downstream sedimentation. This comment remains unaddressed from the previous review.

Surface Water Quality, Page 24, lines 11 - 14

Another activity that may add to potential impacts and cumulative effects to surface water quality is the possible extension of the Central Arizona Project (CAP) pipeline to Sierra Vista, as currently being considered by Bureau of Reclamation (BOR) with an alignment from Green Valley to Rosemont Mine and over the east side of the Santa Rita Mountains to Highway 83 to Sonoita, and continuing to Sierra Vista. This comment remains unaddressed from the previous review.

Ch3 (Biological Resources)

Intro/P1/L8-9

BLM NEPA Handbook (H-1790-1)

The analysis area does not take into account anticipated impacts described in the �Ground Water Quantity� section or our earlier comments and misses the cumulative impacts of other GW water exploitation from existing development and future development in the basin. See Cienega Creek Basin well map � attached below. The BLM has suggested in the past that a major portion of the LCNCA be included in the analysis due largely to indirect impacts on the regional ground water system. When the potential direct and indirect impacts on the regional ground water system are considered, the BLM feels that it would be prudent to include the entire west side of the ground water basin (e.g. from Gardner Canyon to the Del Lago diversion) in the analysis area.

Footnote #1 indicated that hydrologic modeling of drawdown contours were used to determine boundaries analysis area boundaries. The modeling for this geologic unit has extensive bedrock fracturing making the model used of limited reliability in estimating contour with reasonable precision. See BLM comments on GW modeling May 2011.

Biological resources/ Introduction/ 1/17-22 and 32-34

BLM H-1790-1/6.7.1/Affected Environment �The affected environment section of the environmental analysis
is defined
and limited by the identified issues.�

The analysis area is stated as including �(1) springs and drainages that receive surface water discharge from the mine site, including Davidson Canyon wash to its confluence with Cienega Creek; (2) springs and seeps within the area of projected ground water drawdown associated with the mine pit, including those in upper Davidson Canyon; and (3) areas adjacent to the mine site and transportation corridors that may be impacted by noise, dust, and light.� In previous sections (e.g. ES/Groundwater Quantity/9/26-30), the modeling shows drawdown �would not be significant (greater than 5 feet drawdown) �along Cienega Creek�� In Environmental Consequences/Direct and Indirect Effects of Each Alternative/36/3-5, it states that �riparian areas along Cienega Creek� could be potentially disturbed or lost. Therefore, the sections contradict each other, with one section stating that the analysis does not include Cienega Creek at all (other than the Davidson Canyon confluence), the other section stating that Cienega Creek is impacted (but not significantly), the next sentences (32-34) stating that �a reduction in flow from 1 to 3 percent would occur along Cienega Creek from drawdown in the regional bedrock aquifer, resulting in 0.16 mile of lost perennial stream length,� and, finally, �riparian areas along Cienega Creek� could be disturbed or lost (36/3-5). These statements are contradictory. It there are any possible effects to Cienega Creek, other than the Davidson Canyon confluence, then the analysis area should include impacts to the Las Cienegas NCA specifically at Cienega Creek. The analysis area should include Cienega Creek because �a reduction in flow from 1 to 3 percent would occur along Cienega Creek��, ��resulting in 0.16 mile of lost perennial stream length�, modeling shows drawdown �would not be significant (greater than 5 feet drawdown) �along Cienega Creek��, and �riparian areas along Cienega Creek� could be potentially disturbed or lost.

Biological resources/ Introduction/ 1/17-22 and 32-34

Even less than 5 feet drawdown in Cienega Creek and reduction in flow of 1 to 3 percent, 0.16 mile of lost stream length, and disturbed or lost riparian areas (see above) would be significant because of the already existing small amount of surface water present in Cienega Creek, and T&E species and critical habitat are present. The effects analysis to Cienega Creek (upstream of Davidson Canyon confluence) is therefore incomplete.

Biological Resources/Cumulative Effects/60/20-40

BLM H 1790-1/6.8.3.2

The geographic scope is generally based on the natural boundaries of the resource affected, rather than jurisdictional boundaries.

There is no analysis of cumulative effects to critical habitat, special status species, or other wildlife at Empire Gulch or Cienega Creek from anticipated 1- to 3% reduction in flow, drawdown (less than 5 feet), lost perennial stream length (0.16 mile), and disturbed or lost riparian area from the presence of the mine pit (see above comments), with continued drought and climate change.

Biological resources/ Introduction/ 1/17-22 and 32-34

BLM H 1790-1/6.3

Describe the interaction among the effects of the proposed action and
these various past, present, and
reasonably foreseeable actions. This interaction may be: additive� countervailing�
synergistic.

There is also no analysis of interacting or synergistic effects of drawdown, reduction in flow, and lost stream length (see above comments) and potential effects this �drawdown,� �reduction,� �lost stream length,� and �disturbed or lost riparian areas� would have to water quality (e.g. from concentration) of what water would still be available. What effect would this impact have on critical habitat, special status species, and other wildlife at Cienega Creek and Empire Gulch? This is not discussed under Alternatives 2-6/Biological Resources/Surface Water Quality, and is, therefore, incomplete. This is also not discussed under Alternatives 2-6/Biological Resources/Surface Water Quantity, and is, therefore, incomplete.

Biological Resources/Issue 5A:Vegetation/3/15-17.

�The pit, plant, tailings and waste piles, road and utility corridors, and other facilities may result in a permanent change to the vegetation, and reclamation may not restore natural conditions.� Yet it is stated previously (e.g. ES/Soils/ES-12/8-9) that �Reclamation is expected to be successful, approaching historical vegetation climax conditions after 100 years.� These statements are contradictory.

Biological Resources/Issue 5E: Special Status Species or Species of Concern/4/7-11 and Biological Resources/Analysis Methodology, Assumptions, Uncertain and Unknown Information/4/32-41

Lines 7-11 state that �Migratory Birds of Conservation Concern� are included in analysis, but lines 38-40 state that �the 105 species listed as either National Partners in Flight Priority Bird Species or Migratory Nongame Birds of Management Concern�� were addressed in this analysis. These statements are contradictory. In addition, this list (Migratory Birds of Conservation Concern and/or Partners in Flight Priority Bird Species) of birds addressed in the analysis are not included in Table 3.1, Summary of special status plant and animal species that may occur within the analysis area for the proposed Rosemont Copper Mine Project (page 6). Therefore, Table 3.1 is incomplete as it does not include BCC or PIF as stated.