O38 Email from Nov 13 2025 to Dec 9 2025 between Mr Kleinberg and Mr Seele

’ Alejandra From: Mark See! <mseel@langan.com> Sent: Wednesday, November 19, 2025 4:57 PM To: Kleinberg, Sam <SKleinberg@cmeusal.com> Ce: Mazier, Alejandra <AMazier@cmeusal.com> Subject: RE: WEHI This Message is from an external sender. Sam and Alejandra, Attached are the requested output files, which show the analysis groundwater level to be above the infiltration basins; hence the ground is saturated in the analysis. Mark Mark Seel Associate Principal / Vice President LANGAN Direct: 973.560.4986 Mobile: 724.263.2179 File Sharing Link www.langan.com Technical Excellence e Practical Experience e Client Responsiveness NEW JERSEY NEW YORK CONNECTICUT MASSACHUSETTS PENNSYLVANIA VIRGINIA WASHINGTON, DC OHIO ILLINOIS NORTH CAROLINA TENNESSEE FLORIDA TEXAS ARIZONA COLORADO UTAH WASHINGTON OREGON NEVADA CALIFOR NIA ATHENS CALGARY DUBAI LONDON PANAMA From: Kleinberg, Sam <SKleinber: eusal.com> Sent: Friday, November 14, 2025 5:22 PM To: Paul Anderson <pandersonpe@gmail.com>; Mark Seel <mseel@langan.com> Cc: Mazier, Alejandra <AMazier@cmer sal.com>; Hernandez, Nelson <NHernandez@cmeusai1.com>; MacNeill, Ryan <rmacneill@cmeusal.com> Subject: RE: WEHI Good afternoon, Based on our discussion we understand that Langan will forward the high seepage level analysis cases with schematic plot of infiltration basin mound profile

including radius of influence on the analysis sections. Alejandra Mazier will be out Monday through Wednesday and begin reviewing anything you have sent over when she returns. As we discussed we are surprised that the analysis for seepage parallel to the slope would yield a FS on the order of 1.5. We agree that that would be an extreme event which may justify a lower Factor of Safety upon review of relevant standards. We agree that the Hazus mapping likely corresponds to the Feltville sandstone and disintegrated sandstone. As we mentioned in our report that this may begin near Langan Borings LB2 and LB4. Unfortunately neither we nor Langan have been able to locate a report describing the mechanism of the slope mode of failure on which they identified the area of the hazard. In closing we understand that you both did not take any exception to the recommended conditions of approval included in our report. If you need to contact us, you can contact Nelson Hernandez and/or Alejandra Mazier. | hope everyone has a wonderful thanksgiving. Vty, Sam Kleinberg From: Paul Anderson <pandersonpe@gmail.com> Sent: Thursday, November 13, 2025 3:50 PM To: Mark Seel <msee|@langan.com> Cc: Kleinberg, Sam <SKlei if in > Subject: Re: WEHI This Message is from an external sender. Ok, Can we all agree to 2:30? Paul On Thu, Nov 13, 2025 at 3:45 PM Mark Seel <mseel@langan.com> wrote: lam available after 2pm Mark Seel Associate Principal _LANGAN Direct: 973.560.4986 Mobile: 724.263.2179 File Sharing Link .langan.com Technical Excellence e Practical Experience e Client Responsiveness NEW JERSEY NEW YORK CONNECTICUT MASSACHUSETTS PENNSYLVANIA VIRGINIA WASHINGTON, DC OHIO ILLINOIS NORTH CAROLINA TENNESSEE FLORIDA TEXAS ARIZONA COLORADO UTAH WASHINGTON OREGON NEVADA CALIF ORNIA ATHENS CALGARY DUBAI LONDON PANAMA

From: Paul Anderson <panderson mail.com> Sent: Thursday, November 13, 2025 3:39 PM To: Mark Seel <mseel@langan.com>; Sam Kleinberg <SKleinber: eusa1.com> Subject: WEHI| Sam & Mark | Are each of you available for a conference call tomorrow? We would like to discuss the 3 open issues before you go on vacation Sam I can do between 8 and 930 and after 2 pm Paul Paul W. Anderson PE PP CME Anderson Consulting Services LLC 40 Miller Drive Boonton NJ 07005 973-975-0703 This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. Paul W. Anderson PE PP CME Anderson Consulting Services LLC 40 Miller Drive Boonton NJ 07005 r. i 973-975-0703 This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous

transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited. This message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive

is message may contain confidential, proprietary, or privileged information. Confidentiality or privilege is not intended to be waived or lost by erroneous transmission of this message. If you receive this message in error, please notify the sender immediately by return email and delete this message from your system. Disclosure, use, distribution, or copying of a message or any of its attachments by anyone other than the intended recipient is strictly prohibited.

SURFICIAL SLOPE STABILITY Project: WEHI Location: Cross Section A Soil Description: Top Soil Wwe eo i PARAMETERS (cohesion, c= 100 pst Friction Angle, = 30 deg Wt. S0il ap, Ys = 11S pet FS. = FF y= (d (7, - 62.4)Cos*i Tan 6 +c) / (dy, Sin i Cos i) FACTOR OF SAFETY, FS Assumes full soil saturation to ground surface (Critical Slope Radians, i (deg) 0.34 [Critical Slope Angle, i (deg) 19.33 FS for Critical Slope Ratio (horiz.:vert.) Depth, d (fy 2.85H:1V 05 6.32 I 3.54 2 2.14 Project No. Date: 101049801 12/2/25 LANGAN

SURFICIAL SLOPE STABILITY Project: WEHI Project No.: 101049801 Location: Cross Section B Date: 12/2/25 Soil Description: Topsoil es we Qos a me Ze PARAMETERS cohesion, c= 100 psf Friction Angle, 6= 30 ldeg wt. Soin, ¥6= 115 Ipef FS. = F/Fa= (d (y, - 62.4)Cos” i Tan 6 + ¢) / (dy, Sin i Cos i) FACTOR OF SAFETY, FS Assumes fall soil saturation to ground surface [Critical Slope Radians, i (degy 037 (Critical Slope Angle, i (deg) 21.04 FS for Critical Slope Ratio (horiz.:vert) Depth, d (ft) 2.6H:1V. 05 5.88 1 3.28 2 1.98 LANGAN

SURFICIAL SLOPE STABILITY Project: WEHI Project No.: 101049801 Location: Cross Section C Date: 12/2/25 FS. = FF, = (d (7, - 62.4)Cos” i Tan ¢ +c)/ (dy, Sin i Cos i) EACTOR OF SAFETY, FS Assumes full soil saturation to ground surface (Critical Slope Radians, i (deg) 0.41 (Critical Slope Angle, i (deg) 23.50 FS for Critical Slope Ratio (horiz.:vert.) Soil Description: Topsoil PARAMETERS (cohesion, o= 75 pst Friction Angle, 6= 30 deg wt. SOiljan, Ys= 115 pet Depth, d (ft) 23H:1V 0.5 417 1 239 2 1.50 LANGAN

SURFICIAL SLOPE STABILITY Project: WEHI Project No.: 101049801 Location: Cross Section D Date: 12/2/25 Soil Description: Topsoil PARAMETERS cohesion, c= 100 psf Friction Angle, 6 = 30 deg Wt. S0ilans Ye = 115 pet FS. = F/Fa= (d (1, - 62.4)Cos” i Tan $ + ¢) /(d y, Sin i Cos i) FACTOR OF SAFETY, FS. Assumes full soil saturation to ground surface (Critical Slope Radians, i (deg) 0.32 [Critical Slope Angle, i (deg) 18.43 FS for Critical Slope Ratio (horiz.:vert.) Depth, d (ft) 3H:1V 0.5 6.59 1 3.69 2 2.24 LANGAN

356 PART IV SOIL WITH WATER—NO FLOW OR STEADY FLOW > Example 24.2 Given, H =10ft, y, =122.4pcef, ¢ = 12°, submerged slope without seepage. ; Find. Combinations of slope angle and @ which will give failure. Solution. From Eq, 24.3: é = A, cos? i (tani — tan ¢) = 600 cos? i (tani — 0.212) Values of @ and i satisfying this equation are plotted in Fig. E24.2. 200 150 & 100 e 50 0 0 10 20 30 i (degrees) Fig. E24.2 4 Equations 24.2 and 24.3 have practical value in cases where soil overlies a rock surface at shallow depth and parallel to the slope.? In addition, there have been numerous cases in which a shallow slide, with sliding plane parallel to the slope, develops in a soil mass of great depth. This happens because the strength param- eters of an overconsolidated soil are not constant with depth. A typical situation is depicted in Fig. 24.7. Here weathering has weakened the soil near the surface, destroying most of the cohesion intercept. The sliding plane develops on the stronger, less weathered soil which exists at depth. Equations 24.2 and 24.3 may be used to analyze the equilibrium of such slides. If a clay has no cohesion intercept, then of course the maximum slope angle is related directly to the friction angle, as in the case of sands. The safety factor F for a slope is usually defined as P= available shear strength ~~ shear stress required for equilibrium (24.4) This safety factor must be evaluated for the most critical surface through the slope. For the case of soil having vertical thickness H overlying rock, this critical surface is the soil-rock interface. Thus, for seepage parallel to the slopes pattatang E+ nH cos*itan g r Hsin icosi (245) » See page 431 of Taylor (1948) for a similar equation which applies when the top flow line is parallel to but at some distance below the sloping ground surface. Shear stress required for equilibrium and shear strength Weathered shale Unweathered shale Fig. 24.7 Development of failure plane within weathered sx or rock, 7 If the strength parameters ¢ and ¢ vary with depth, as Fig. 24.7, then F must be evaluated for several dept’ until the minimum value of F is found. For a slope with a given inclination and a given seepa condition, the shear stress required for equilibrium c: be determined with great accuracy. Uncertainty as tot stability hence arises from uncertainty as to the shc strength, The