6-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER
PURSUANT TO RULE 13a-16 OR 15d-16 UNDER
THE SECURITIES EXCHANGE ACT OF 1934

For the month of May, 2008.

Northgate Minerals Corporation

(Translation of registrant’s name into English)

815 Hornby Street, Suite 406
Vancouver, British Columbia
Canada V6Z 2E6

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F o   Form 40-F þ

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):             

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes o          No þ

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-                    

SIGNATURES

Pursuant to the requirements of the Securities and Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereto duly authorized.

	Registrant:
	Northgate Minerals Corporation
Date: May 16, 2008
	By:	/s/ Jon A. Douglas
	Name:	Jon A. Douglas
	Title:	Senior Vice President and Chief Financial Officer

EXHIBIT INDEX

Exhibit
Number	Description
99.1	Related Supplementary Note Entitled “Item 18 Reconciliation to United States Generally Accepted Accounting Principles for the years ended December 31, 2007 and 2006” and the Auditor’s Report thereon.
99.2	Related Supplementary Note Entitled “Reconciliation to United States Generally Accepted Accounting Principles for the three months ended March 31, 2008 and 2007”

EX-99.1

Exhibit 99.1

	KPMG LLP	Telephone	(604) 691-3000
	Chartered Accountants	Fax	(604) 691-3031
	PO Box 10426 777 Dunsmuir Street	Internet	www.kpmg.ca
	Vancouver BC V7Y 1K3
	Canada

AUDITORS’ REPORT ON RECONCILIATION TO UNITED STATES GAAP

To the Board of Directors of Northgate Minerals Corporation

On February 18, 2008, we reported on the consolidated balance sheets of Northgate Minerals Corporation (the Company) as at December 31, 2007 and 2006 and the consolidated statements of operations and comprehensive income, changes in shareholders’ equity and cash flows for the years then ended which are included in the annual report on Form 40-F for the year ended December 31, 2007. In connection with our audits conducted in accordance with Canadian generally accepted auditing standards and the standards of the Public Company Accounting Oversight Board (United States) of the aforementioned consolidated financial statements, we also have audited the related supplemental note entitled Item 18 Reconciliation to United States Generally Accepted Accounting Principles. This supplemental note is the responsibility of the Company’s management. Our responsibility is to express an opinion on this supplemental note based on our audits.

In our opinion, such supplemental note, when considered in relation to the basic consolidated financial statements taken as a whole, presents fairly, in all material respects, the information set forth therein.

KPMG LLP (signed)
Chartered Accountants

Vancouver, Canada
February 18, 2008

KPMG LLP, a Canadian limited liability partnership is the Canadian
member firm of KPMG International, a Swiss cooperative.

NORTHGATE MINERALS CORPORATION

Supplementary Note
Item 18 Reconciliation to United States Generally Accepted Accounting Principles
Years ended December 31, 2007 and 2006

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

Northgate Minerals Corporation (the “Corporation”) follows generally accepted accounting principles in Canada (“Canadian GAAP”) which are different in some respects from those applicable in the United States and from practices prescribed by the United States Securities and Exchange Commission (“U.S. GAAP”). The Corporation has previously prepared a reconciliation of the significant measurement differences between Canadian GAAP and U.S. GAAP in accordance with Item 17 of Form 20-F, which is included in the Corporation’s 2007 Annual Report on Form 40-F. For purposes of a Registration Statement on Form F-10, the Corporation is also required to reconcile additional significant disclosure differences in accordance with Item 18 of Form 20-F. The additional significant disclosure differences between Canadian GAAP and U.S. GAAP are as follows:

A. Stock-Based Compensation

As of December 31, 2007, there was $3,900,000 of unrecognized stock-based compensation cost related to 2,437,700 unvested stock options. This cost is expected to be recognized over a weighted-average period of approximately 3.73 years. The total intrinsic value of options exercised in 2007 and 2006 was $1,500,000 and $2,500,000, respectively. The aggregate intrinsic value of outstanding stock options was $2,900,000 at December 31, 2007. The aggregate intrinsic value of the exercisable options was $2,100,000.

B. Current Assets

Balance Sheet

For Canadian GAAP purposes, the Corporation combines all accounts receivables and prepaid expenses on the consolidated balance sheet. The form and content of financial statements as presented in Regulation S-X, Rule 5-02 requires segregation of current assets based on their nature and materiality, and requires that prepaid expenses be presented separately on the balance sheet. The presentation of receivables and other current assets as required by US GAAP at December 31, 2007 and December 31, 2006 is as follows:

	December 31, 2007		December 31, 2006
Concentrate receivables	$	3,760	$	2,760
Unrealized gain on copper forward contracts		7,124		11,853
Lease and interest receivable		1,122		—
Other receivables		2,008		1,497
Prepaid expenses		3,087		1,850
Total concentrate settlements and other receivables	$	17,101	$	17,960

Statement of Cash Flows

Cash flows from receivables and other current assets are included in aggregate in the consolidated statement of cash flows as a component of changes in operating working capital. The detailed cash flows are as follows:

	December 31, 2007			December 31, 2006
Decrease (Increase) in concentrate receivables	$	(1,000	)	$	14,013
Increase in interest receivables		(256	)		—
Increase in other receivables		(606	)		(785	)
Increase in prepaid expenses		(1,237	)		(74	)
		(3,099	)		(13,154	)

NORTHGATE MINERALS CORPORATION

Supplementary Note
Item 18 Reconciliation to United States Generally Accepted Accounting Principles
Years ended December 31, 2007 and 2006

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

C. Current Liabilities

Balance Sheet

For Canadian GAAP purposes, the Corporation combines accounts payable and accrued liabilities on the consolidated balance sheet. The form and content of financial statements as presented in Regulation S-X, Rule 5-02 requires segregation of payables and other current liabilities based on their nature and materiality. The presentation of current payables and other current liabilities as required by US GAAP at December 31, 2007 and December 31, 2006 is as follows:

	December 31, 2007		December 31, 2006
Trade payables	$	5,860	$	1,794
Accrued liabilities		19,644		17,547
Unrealized loss on copper hedges		2,975		—
Payroll liabilities		2,211		1,808
Income and mineral taxes payable		3,311		514
Other payables		1,860		360
Total accounts payable and accrued liabilities	$	35,861	$	22,023

Statement of Cash Flows

Cash flows from payables, accrued liabilities and other current liabilities are included in aggregate in the consolidated statement of cash flows as a component of changes in operating working capital. The detailed cash flows are as follows:

	December 31, 2007		December 31, 2006
Increase (decrease) in trade payables	$	4,066	$	(853	)
Increase in accrued liabilities		2,097		4,301
Increase in payroll liabilities		403		56
Increase (decrease) in income and mineral taxes payable		2,797		(472	)
Increase in other payables		1,511		190
	$	10,874	$	3,222

D. Shareholder’s Equity

Regulation S-X, Rule 5-02 requires various details related to common shares be disclosed on the face of the balance sheet. This includes the title of issue and number of shares authorized, the par value of authorized shares, and the number of shares issued or outstanding. For Canadian GAAP purposes, the title of issue and number of shares authorized and their par values are disclosed in Note 12 of the consolidated financial statements for the year ended December 31, 2007 included in the 2007 Annual Report on Form 40-F. The number of shares outstanding is reported in the consolidated statement of changes in shareholder’s equity.

E. Income Taxes

For the year ended December 31, 2007, the Corporation adopted the requirements of FIN 48 “Accounting for Uncertainty in Income Taxes” (“FIN 48”). FIN 48 requires the disclosure of the Corporation’s policy for classification of interest and penalties and a description of tax years that remain subject to examination. The Corporation classifies interest on underpayment of income taxes as interest expense and tax penalties are recognized in the statement of operations as other expense. The Corporation’s accounting treatment for interest and penalties is the same under Canadian and US GAAP.

NORTHGATE MINERALS CORPORATION

Supplementary Note
Item 18 Reconciliation to United States Generally Accepted Accounting Principles
Years ended December 31, 2007 and 2006

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

Tax years subsequent to 2004 remain open for examination by the Canada Revenue Agency. However, if the Corporation utilizes prior years’ tax loss carry forwards in the future, those losses can be challenged in the year they are used even though the tax year is statute barred.

US GAAP also requires disclosure of the facts and circumstances which support the realizeability of deferred tax assets. Management believes that it is more likely than not that the results of future operations will generate sufficient taxable income to realize the deferred tax assets. The deferred tax assets consist predominantly of temporary differences associated with British Columbia (“BC”) mineral taxes and federal exploration tax credits.

The BC mineral tax temporary differences are specific to the income-generating asset and can be applied indefinitely against income for mineral tax purposes related to the Kemess South mine. Exploration tax credits may be carried forward 20 years or back 3 years to reduce any taxes payable. The Corporation has prepared a life of mine projection which supports the recognition of a deferred tax asset to reduce future taxes.

The Corporation has a significant amount of capital losses for Canadian tax purposes which are available indefinitely to reduce taxes payable on future capital gains. Management believes that future income from capital gains is not likely and has therefore recognized a full valuation allowance against this deferred tax asset.

F. Interest Income and Expense

Interest income is reported net of interest expense for Canadian GAAP purposes. The gross amount of interest income and interest expense for the years ended December 31, 2007 and 2006 are as follows:

	December 31, 2007			December 31, 2006
Interest Income	$	17,610		$	5,267
Interest Expense		(486	)		(1,254	)
	$	17,124		$	4,013

G. Depreciation Expense

US GAAP requires disclosure if depreciation is not included as a component of cost of sales. For the Corporation, depreciation in inventory is included in depreciation expense when the related inventory is sold.

H. Financial Instruments

US GAAP requires disclosures concerning the Corporation’s risk exposure from the use of financial instruments. These risks include market risk and credit risk.

Market Risk

Market risk is the risk that changes in market prices, such as commodity prices, foreign exchange rates and interest rates, will affect the Corporation’s income or the value of its holdings of financial instruments. The Corporation manages this risk such that it controls this exposure within acceptable parameters while optimizing the return on risk.

Commodity Price Risk — The Corporation is exposed to commodity price risk through the price of gold and copper and also through various input prices such as fuel and electricity. The Board of Directors has established a Hedging Committee, which assists management in the identification and analysis of price risks and potential strategies to mitigate this risk.

NORTHGATE MINERALS CORPORATION

Supplementary Note
Item 18 Reconciliation to United States Generally Accepted Accounting Principles
Years ended December 31, 2007 and 2006

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

The Corporation reviews major input prices on a regular basis and may enter into long-term contracts to mitigate the price volatility.

The Corporation monitors the price of commodities continuously and considers the risk exposure of fluctuating prices. In managing that risk, the Corporation is cognizant that investors generally seek exposure to the underlying commodities, particularly gold, through their investment.

All of the Corporation’s future gold production is unhedged and is fully exposed to future price movements. The Corporation has entered into a series of forward contracts with respects to its copper production; the terms are disclosed in Note 15 of the consolidated financial statements for the year ended December 31, 2007 included in the 2007 Annual Report on Form 40-F.

Currency Risk — The Corporation is exposed to currency risk on its financial assets and liabilities denominated in other than United States dollars. The Corporation incurs a significant amount of its operating costs in Canadian dollars.

Interest Rate Risk — The Corporation is exposed to interest rate risk on its short-term loan and its capital leases. The short-term loan bears interest at LIBOR plus 100 basis points. The capital leases bear interest at a fixed rate.

Credit and Concentration Risk

Credit risk is the risk of potential loss to the Corporation if a customer or counterparty to a financial instrument fails to meet its contractual obligations. It arises principally from the Corporation’s receivables and investment securities. It may also arise on the Corporation’s copper forward contracts.

In general, the Corporation manages its credit exposure with respect to operational matters by transacting only with reputable, highly-rated counterparties. The Corporation monitors the financial condition of its customers and counterparties to contracts.

Concentrate produced at Kemess is sold under a long-term contract to Xstrata Canada Corporation (“Xstrata”), a wholly owned subsidiary of the publicly traded international mining company, Xstrata plc. Kemess gold/copper concentrate is of a quality that is readily saleable to a number of smelters under current market conditions. In the event that Xstrata was unable to purchase the Kemess concentrate, it could be sold to other smelters once appropriate logistical arrangements were put in place.

The Corporation may also be exposed to credit risk on its copper forward contracts to the extent that the counterparty fails to meet its contractual obligation. The Corporation manages this risk by contracting only with a reputable counterparty and monitoring the party’s financial condition.

The Corporation limits its exposure to credit risk on investments by investing only in securities rated AAA by credit rating agencies such as S&P and Moody’s. Management continuously monitors the fair value of its investments to determine potential credit exposures. The Corporation included further disclosures concerning its Auction Rate Securities investments in Note 8 of the consolidated financial statements for the year ended December 31, 2007 included in the Annual Report on Form 40-F.

Short-term excess cash is invested in R1/P1/A1 rated investments including money market funds, direct obligation commercial paper, bankers’ acceptances and other highly rated short-term investment instruments, which are recorded as cash and cash equivalents. Any credit risk exposure on cash balances is considered negligible as the Corporation places deposits only with major established banks in the countries in which it carries on operations.

NORTHGATE MINERALS CORPORATION

Supplementary Note
Item 18 Reconciliation to United States Generally Accepted Accounting Principles
Years ended December 31, 2007 and 2006

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

The carrying amount of financial assets represents the maximum credit exposure. As at December 31, 2007, the Corporation’s gross credit exposure is as follows:

	December 31, 2007		December 31, 2006
Cash and cash equivalents	$	266,045	$	262,199
Concentrate settlements and other receivables		17,101		17,960
Other assets (restricted cash)		69,125		14,940
Unrealized gain on copper forward contracts		7,124		11,853
Long term receivables		25,117		—
Unrealized gain on other hedge contracts		10,646		—
Auction rate securities		69,397		—
	$	464,555	$	306,952

Fair Value Measurement

Commodity contracts are valued by determining the difference between contractual forward rates and the current forward prices for the residual maturity of the contracts. When in a gain position, the fair value of the contracts is discounted to the balance sheet date using the 12 month LIBOR rate at that date, plus a spread representing the risk premium of the counterparty. When in a loss position, a spread representing the risk premium of Northgate is added to LIBOR for the discounting of the fair value of the contracts. The net loss from the change in fair value of the forward contracts of $22,747,000 for the year ended December 31, 2007 (2006 — net gain of $24,920,000) is included in revenues.

I. Significant Risks and Uncertainties

US GAAP requires the disclosure of concentrations of labour subject to collective bargaining agreements (“CBA”). All hourly employees at the Kemess South mine are members of the International Union of Operating Engineers (Local 115) which are covered by a CBA and account for 69% of all Northgate employees. On December 31, 2007, the current CBA at Kemess expired and the Corporation is currently negotiating a new three-year agreement.

EX-99.2

Exhibit 99.2

NORTHGATE MINERALS CORPORATION

Supplementary Note
Reconciliation to United States Generally Accepted Accounting Principles
For the three months ended March 31, 2008 and 2007 (unaudited)

(All dollar amounts are stated in United States dollars unless otherwise indicated.)

The interim consolidated financial statements of the Corporation as at March 31, 2008 and for the three months ended March 31, 2008 and 2007 have been prepared in accordance with Canadian generally accepted accounting principles (“GAAP”) for interim financial reporting. Such principles differ in certain respects from United States (“US”) GAAP. For information on material differences between Canadian GAAP and US GAAP, references should be made to the Supplementary Note, Reconciliation to United States Generally Accepted Accounting Principles for the years ended December 31, 2007 and 2006 included in the Corporation’s Annual Report on Form 40-F and the Supplementary Note, Item 18 Reconciliation to United States Generally Accepted Accounting Principles for the years ended December 31, 2007 and 2006 (collectively, the “US GAAP Reconciliations”), which are incorporated by reference in this filing.

The financial information presented in the interim consolidated financial statements and in this reconciliation to US GAAP is unaudited. However, in the opinion of management such information reflects all adjustments, consisting solely of normal recurring adjustments, which are necessary for a fair statement of the results for the interim periods presented.

The significant measurement differences listed in the US GAAP Reconciliations that are applicable to the interim consolidated financial statements as at March 31, 2008 and for the three months ended March 31, 2008 and 2007, are as follows:

– The United States Securities and Exchange Commission (“S.E.C.”) staff have indicated that their interpretation of Statement of Financial Accounting Standards No. 144 (“SFAS 144”), “Accounting for the Impairment or Disposal of Long-Lived Assets", requires mineral property costs be expensed as incurred until commercially mineable deposits are determined to exist within a particular property, as cash flows cannot be reasonably estimated prior to such determination. Under Canadian GAAP, certain exploration expenses have been capitalized while for US GAAP purposes, these costs would be recognized as exploration expenses as incurred. As a result, under US GAAP, differences exist in the carrying value of mineral property, plant and equipment, the recognition of exploration expenses, net earnings for the period, and the classification of these costs in the consolidated statement of cash flows.

– Prior to 2003, the Corporation owned 95% of the Kemess Mine and recognized minority interest for the 5% interest it did not own. For US GAAP purposes, differences between Canadian GAAP and US GAAP were allocated between the Corporation and minority interest based on their respective interests. During 2003, the Corporation purchased the 5% interest it did not already own and allocated the excess purchase price to mineral properties. As a result of differences between Canadian and US GAAP previously allocated to minority interest, a difference between Canadian GAAP and US GAAP arose on acquisition of the minority interest related to the amount allocated to mineral properties. This difference is being amortized over the life of the Kemess mine using the units of production method. As a result, under US GAAP, differences exist in the carrying value of mineral property, plant and equipment and in the amount of depreciation and depletion expense.

– Under U.S GAAP, share purchase warrants denominated in a currency that is not the functional currency of the Corporation should be accounted for as a liability, with the change in fair value recorded through the statement of operations. Under Canadian GAAP, share purchase warrants are accounted for as equity. All share purchase warrants were exercised or expired in 2006. Share

NORTHGATE MINERALS CORPORATION

Supplementary Note
Reconciliation to United States Generally Accepted Accounting Principles
For the three months ended March 31, 2008 and 2007 (unaudited)

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

capital and contributed surplus would increase for US GAAP purposes to account for the fair value of all warrants which were exercised or expired in 2006. A corresponding decrease in retained earnings would also be recognized.

–	In 2000, the Corporation issued 1,500,000 warrants to Brookfield Asset Management, a former significant shareholder of the Corporation, relating to advisory services and financing provided in connection with the acquisition of the Kemess Convertible Royalty. Under US GAAP, the granting of these warrants would be considered a financing fee with the fair value being a cost associated with the acquisition. As a result, under US GAAP, differences exist in the carrying value of mineral property, plant and equipment and shareholders’ equity as at March 31, 2007. For US GAAP purposes, these costs were included in a writedown recorded by the Corporation in its quarter ended September 30, 2007.
–	Under US GAAP, all derivative financial instruments which do not qualify as a hedge under SFAS 133 are recognized in the consolidated financial statements and measured at fair value regardless of the purpose or intent for holding them, with changes in the fair value of derivative financial instruments recognized in earnings.
	With the adoption of CICA Handbook Section 3855, Financial Instruments — Recognition and Measurement, Section 3865, Hedges, Section 1530, Comprehensive Income and Section 3251, Equity, on January 1, 2007, the Corporation’s accounting for derivative financial instruments and hedging activities are substantially harmonized with US GAAP. Upon adoption, the Corporation elected to discontinue hedge accounting for its gold forward sales contracts. Consistent with US GAAP, these contracts have been recognized in the balance sheet at January 1, 2007 at fair value with changes in fair value charged to earnings for the three months ended March 31, 2007. However, for Canadian GAAP purposes, the effect of the adoption of these new standards and the discontinuance of hedge accounting resulted in a charge to accumulated other comprehensive income on the balance sheet at January 1, 2007. A portion of this amount is reclassified to net earnings for Canadian GAAP as the related forward contracts are settled. This reclassification does not exist under US GAAP. As a result, under US GAAP, differences exist in revenues and other comprehensive income for the three months ended March 31, 2007, and in accumulated other comprehensive income and retained earnings as at March 31, 2007. All contracts had settled by December 31, 2007.
	Prior to January 1, 2004, a difference between US and Canadian GAAP existed with respect to the use of hedge accounting for the Corporation’s gold forward sales contracts. As a result, under US GAAP, differences exist in mineral property, plant and equipment and retained earnings as at March 31, 2007. For US GAAP purposes, this amount was included in a writedown recorded by the Corporation in its quarter ended September 30, 2007.
–	In 2006, FASB issued FIN 48 “Accounting for Uncertainty in Income Taxes, an Interpretation of FASB Statement 109". This interpretation prescribes a recognition threshold and measurement criteria for the financial statement recognition of a tax position taken or expected to be taken in a tax return. The Corporation was required, effective January 1, 2007 for US GAAP purposes only, to determine whether it is more likely than not that a tax position will be sustained upon examination and such positions that meet this threshold will be measured at the most likely amount to be realized upon settlement. The Corporation has reviewed its tax positions and determined that the application of FIN 48 does not result in any material adjustment for US GAAP purposes.

NORTHGATE MINERALS CORPORATION

Supplementary Note
Reconciliation to United States Generally Accepted Accounting Principles
For the three months ended March 31, 2008 and 2007 (unaudited)

(All dollar amounts are stated in United States dollars unless otherwise indicated.
Tables are expressed in thousands of United States dollars, except share and per share amounts.)

As described in the US GAAP Reconciliations, there are certain recently issued US accounting pronouncements that were not effective for the year ended December 31, 2007 but would have been effective for the three month period ended March 31, 2008 had the Corporation prepared its interim consolidated financial statements under US GAAP. The Corporation has concluded that the impact of adopting these recently issued US accounting pronouncements will not be material for the 2008 fiscal year.